The Mermaid Mask Wiki
Solve Captain Mortuga's locked-room murder with Detective Grimoire and Sally. Explore the Mortuga submarine, inspect 3D clues, question suspects, and master every puzzle.
The Mermaid Mask Resources
Everything you need to solve the Mortuga submarine case in The Mermaid Mask
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The Mermaid Mask ios: Release Status & Mobile Walkthrough Guide
Explore The Mermaid Mask ios availability, mobile play options, and a complete walkthrough for Detective Grimoire's submarine murder mystery in 2026.
The Mermaid Mask Switch Release Date: 2026 Launch Schedule
Check the official The Mermaid Mask switch release date, gameplay features, and submarine investigation mechanics for the 2026 Nintendo Switch launch.
The Mermaid Mask Release Date: Launch Schedule & Investigation Guide
Discover The Mermaid Mask release date, global launch times, and essential investigation tips for solving the Magnus Mortuga murder mystery in 2026.
The Mermaid Mask price: Platform Cost & Edition Guide
Discover The Mermaid Mask price across Steam, Nintendo Switch, and PS5. Compare editions, regional pricing, and find the best deals.
The Mermaid Mask guide: Walkthrough, Puzzles & Clues
Master the demo of The Mermaid Mask with our guide. Solve the serpent dial puzzle, analyze the crime scene, and find every hidden clue in Silkworm-on-Sea.
The Mermaid Mask edge: Puzzle Solutions & Case Tactics
Master Captain Mortuga's locked-room murder. Learn how to secure the ultimate strategic edge, solve complex puzzles, and find every hidden clue.
The Mermaid Mask platforms: Complete Availability & System Guide
Explore all available The Mermaid Mask platforms, system requirements, and handheld compatibility for SFB Games' latest mystery adventure in 2026.
The Mermaid Mask PS5: Investigation Guide & Gameplay Tips
Master the submarine mystery in The Mermaid Mask ps5. Explore investigation mechanics, character roles, and technical performance on PlayStation 5.
The Mermaid Mask hltb: Completion Time & Story Length
Discover the estimated playtimes for The Mermaid Mask hltb. Learn the main story length, 100% completionist run duration, and chapter-by-chapter progression.
The Mermaid Mask typewriter puzzle: Walkthrough & Solution
Solve the typewriter puzzle in The Mermaid Mask with our step-by-step walkthrough. Decode suspect clues and unlock the Captain's safe easily.
The Mermaid Mask Full Playthrough: Step-by-Step Walkthrough
Master the investigation in Silkworm on Sea with our The Mermaid Mask full playthrough guide, covering every suspect and puzzle solution.
The Mermaid Mask sfb games: Detective Strategy & Puzzle Guide
Master the mysteries of Silkworm Sea with our guide to The Mermaid Mask sfb games. Learn about 3D clues, the Mind Game, and submarine puzzles.
The Mermaid Mask Walkthrough
Follow the mandatory investigation route from Stonetop Inn to the final confrontation aboard the Mortuga submarine. Each section stops before revealing later story twists.
The Mermaid Mask is structured around an opening investigation and the main murder case, The Curse in the Cauldron. Use this route to collect required evidence, unlock every area, question the full crew, and recover when the next progression trigger is unclear.
Prologue: The Beginning
Opening sequence
Prologue
Review the case and wake Sally.
- Inspect The Hex of the Helmsmen book lying near Sally.
- Open the red Case File and read the locked-room murder summary.
- Interact with Sally to begin the journey to the submarine.
Trigger: Leave the inn after Sally joins Grimoire.
Find the transport arranged by Captain Seafoam.
- Inspect the square, signs, fountain, and unusual green light.
- Talk to Sally after examining the glowing area.
- Wait for the Mortuga submarine to surface and board it.
Trigger: Enter the submarine from the Fore Deck.
Enter the ship and restore the first interior light.
- Inspect the glowing carved buoy on the Fore Deck.
- Enter the Parlor and let Sally operate the lever that lights the pink flame.
- Read the warning attached to the Control Room window.
- Note that the Control Room and murder floor are initially inaccessible.
Trigger: Move through the available corridor toward the Mess Hall.
Open the snake cabinet.
- Inspect the cards, cookware, lamps, candles, and cabinet.
- Treat each shape as its number of sides.
- Set the four displays to triangle for 3, square plus pentagon for 9, triangle plus square for 7, and square for 4.
Trigger: Finish inspecting the opened cabinet and continue to the Illusion Theatre.
Examine the locked-room crime scene.
- Inspect the ragged cloth connected to The Stargazing Girl.
- Examine the upside-down illusion poster.
- Inspect the chalk outline, the ancient stone cauldron, and the surrounding stage.
- Review every highlighted point on the cauldron before opening the deduction.
Trigger: Complete the first case conclusion.
Form the opening conclusion.
- Select Magnus Mortuga as the person who unlocked the cauldron.
- Select the conclusion that he was killed by what was inside it.
- Confirm the deduction to begin the main investigation.
Trigger: Chapter One, The Curse in the Cauldron, begins.
Chapter One: The Curse in the Cauldron
Investigation and progression spoilers
Unlock the Control Room
Solve the doll portrait and obtain the Glass Eyeball.
- Read the newspaper about the Lady of the Looking Glass and the sea-serpent report on its reverse.
- Combine the six portrait cards into three complete girls.
- Place Patricia in the center with the medium-sized doll.
- Use the enlarging and shrinking lenses on the outer dolls.
- Place the fish-eye lenses over the faces of the left and right girls.
Trigger: Collect the Glass Eyeball from the completed mechanism.
Reveal Symmetry Silkmoth.
- Return to the Parlor and inspect the watching eyes near the Control Room door.
- Go back to the Child's Room.
- Interact with the blinking painting to reveal Symmetry Silkmoth.
- Ask Symmetry about herself, the submarine, the crew, and every available clue.
Trigger: Return to the Control Room after completing Symmetry's initial interview.
Meet Sinthia Seafoam and recover the Captain's Log.
- Question Sinthia about Mortuga, her new command, Symmetry, and the other crew members.
- Inspect the Submarine Blueprint, wheel, captain's jacket, and control equipment.
- Connect the red cable from socket 1 to 9, blue from 3 to 11, and yellow from 6 to 12.
- Take the Captain's Log from the opened compartment.
- Present the new evidence to Sinthia before leaving.
Trigger: The bunk rooms and additional crew interviews become part of the active route.
Search the Crew Quarters
Open the pig safe and search Sinthia's bunk.
- Read the Movie Magazine.
- Set the pig-safe number network so the top branches read 3, 4, 1 and total 8, while the second branches read 2, 3, 1 and total 6.
- Align the lower totals as 5, 9, and 2.
- Take the gloomy underwater photograph from the safe.
- Show the photograph to Sinthia and Symmetry.
- Return to Sinthia's mattress after Symmetry points out the concealed material.
Trigger: Collect the Inn Deeds hidden beneath the mattress.
Interview Dirk Dansom and J.D. Wirman.
- Ask both men about themselves, Mortuga, the submarine, and the entire suspect list.
- Solve Dirk's phone lock by making every connected channel begin and end with matching symbols.
- Read the unlocked calls, messages, and emails.
- Rotate the typewriter's inner and outer rings so the five displayed patterns follow the required 45-degree transformations.
Trigger: Recover the handwritten letter addressed to Wirman from Ibis.
Meet the Remaining Crew
Interview Dr. Zacharias Zephyr.
- Ask Zephyr about Mortuga, his dream work, and every crew member.
- Inspect the Hex Bottle, Dream Helmet, Fog Ball, and other interactive equipment.
- Rotate and open each 3D clue until every inspection point has been registered.
Trigger: Add Zephyr's testimony and dream-related evidence to the notebook.
Interview Mariana Moon and locate the crew-position puzzle.
- Question Mariana about her historical research and the other passengers.
- Search the sacks and collect the Silkwirm Map.
- Inspect the large pinboard representing the submarine.
- Leave the pinboard unfinished until every living crew member has been met.
Trigger: Return after interviewing Godrik Gripp and Madam Tadpole.
Open Mortuga's private room.
- Use the Glass Eyeball in the eye-shaped lock.
- Push the inserted eye to release the internal key.
- Inspect the broken handheld radio, table bell, ship in a bottle, and the painting titled Her.
- Rotate every collected object and examine its hidden sides.
Trigger: Add Mortuga's private possessions to the evidence list.
Interview Godrik Gripp and repair the compass.
- Inspect three shop items to begin Gripp's full conversation.
- Question him about the ship, Mortuga, his merchandise, and the crew.
- Set the yellow compass to point left, the blue compass down, the pink compass toward roughly two o'clock, and the red compass toward the upper-left.
- Collect the repaired compass.
Trigger: Present the repaired object and related evidence to the characters who recognize it.
Interview Madam Tadpole.
- Ask Tadpole about her mermaid identity, Mortuga, and every suspect.
- Record her account of a glowing-eyed figure on the Fore Deck.
- Compare her description of its language with the shapes visible behind the cauldron.
- Inspect the diving helmet and the other grotto equipment.
Trigger: All eight primary suspects have now been introduced.
Connect Testimony and Evidence
Complete the crew-location pinboard.
- Place each living crew member at the room where they are currently stationed.
- Place Mortuga's portrait outside the submarine diagram because he is dead.
- Confirm the completed layout to establish the ship's current population and room structure.
Trigger: Additional testimony and personal-investigation topics become available.
Identify Mariana's disguised recording device.
- Show Mariana the pipe-shaped object and related mechanical evidence.
- Establish that the pipe is a Dictaphone used to record crew conversations.
- Listen to every available recording.
- Present significant recorded statements to the people involved.
Trigger: New contradiction and motive topics appear in character interviews.
Unlock every personal investigation.
- Present each newly collected clue to all characters with an available reaction.
- Revisit Sinthia and Symmetry after finding the photograph and Inn Deeds.
- Revisit Dirk and Wirman after unlocking the phone and letter.
- Revisit Zephyr, Mariana, Gripp, and Tadpole after solving their room puzzles.
- Use the notebook to locate characters who still have unread evidence reactions.
Trigger: A character's personal investigation opens after the required testimony and evidence have been collected.
Complete the suspect investigations.
- Fill each conclusion with the statement supported by the collected testimony.
- Attach the physical clue that directly proves the selected conclusion.
- After an incorrect selection, use Grimoire and Sally's expanded comments to narrow the answer.
- Repeat the interview loop whenever the game indicates that a relevant clue is still missing.
Trigger: Complete all required character investigations.
Final Confrontation
Reconstruct the locked-room murder.
- Finish all remaining room puzzles and evidence inspections before starting the confrontation.
- Review the cauldron, stage, hidden mechanisms, crew movements, and Mortuga's possessions.
- Build the timeline using only conclusions already proven in the personal investigations.
- Present the matching physical evidence when each final deduction prompt appears.
Trigger: Confirm the completed murder reconstruction to enter the ending sequence.
The culprit, method, and final revelations are intentionally omitted.
The Mermaid Mask Puzzle Solutions
Find spoiler-controlled hints and direct answers for the submarine's object puzzles, locks, deduction devices, and investigation minigames.
Most puzzles rely on rotating fully modeled objects, matching visual categories, or connecting evidence rather than entering traditional passwords. Open the hint first, then reveal the solution only when the mechanism remains unclear.
Snake Cabinet Number Dials
Hint: Each shape represents its number of sides. Combine shapes when a display requires a larger total.
Solution: Set 3 to one triangle, 9 to one square plus one pentagon, 7 to one triangle plus one square, and 4 to one square.
Reward: Opens the cabinet and advances the route toward the crime scene.
Portrait Cards and Lenses
Hint: Patricia owns the medium-sized doll, while Jennifer and Margaret look toward her from opposite sides.
Solution: Join the six cards into three complete girls. Put Patricia in the center and leave her doll unchanged. Use the magnifying and shrinking lenses on the two outer dolls, then place the fish-eye lenses over the faces of the left and right girls.
Reward: Glass Eyeball
Switchboard Cables
Hint: Only three connections are needed, and each cable joins a socket on the upper row to one on the lower row.
Solution: Connect the red cable from socket 1 to socket 9, the blue cable from socket 3 to socket 11, and the yellow cable from socket 6 to socket 12.
Reward: Captain's Log
Nine-Piece Hexagonal Mechanism
Hint: Build continuous colored rings before worrying about the cords.
Solution: Arrange all nine pieces into the hexagonal frame so the beveled edges form uninterrupted concentric bands. The magenta and red outer panels must surround a continuous yellow band, the purple inner wedges must face the center, and every cord must terminate at a matching peg or at the central joint.
Reward: Completes the Control Room mechanism and registers its associated evidence.
Pink Pig Safe
Hint: The numbers on connected branches are added to produce the fixed totals at their ends.
Solution: Set the upper movable numbers to 3, 4, and 1 for a total of 8. Set the second row to 2, 3, and 1 for a total of 6. The three lower connected totals should read 5, 9, and 2.
Reward: Gloomy Underwater Photograph
Dirk's Phone Lock
Hint: Every route has a symbol at both endpoints. The tiles between them must create one continuous matching channel.
Solution: Solve the crossing routes first. Rotate and place each tile so channel A connects identical crossed symbols from left to right, while channels B, C, and D connect their matching top and bottom symbols without a broken line. Once all four routes are continuous, the phone unlocks.
Reward: Dirk's calls, messages, and emails
Typewriter Ring Code
Hint: The five symbols are not separate pictures. Each is the previous pattern after a fixed rotation.
Solution: Use the center preview to compare neighboring target symbols. Rotate the three inner dials and three outer rings so every adjacent pattern changes by 45 degrees while preserving the same component arrangement.
Reward: Letter from Ibis to J.D. Wirman
Bottle Caps
Hint: The prose clues describe visible or physical properties of the six bottles.
Solution: Place the crescent cap on the bottle with the crimson-colored label, the spade cap on the effervescent bottle, the bird-skull cap on the bottle emitting vapor, the sun-shaped cap on the fast-dripping bottle, the hand cap on the viscous bottle, and the eye cap on the bottle with the conspicuous X.
Reward: Completes the Hex Bottle inspection.
Skull Classification Grid
Hint: The column symbols describe head decorations. The row symbols describe facial features.
Solution: Sort the skulls by ornament across the columns: red marking, side-marked skull, crescent marking, and horns. Sort them by face down the rows: narrow or closed eyes, prominent teeth or jaw, and large round eyes. Rotate each skull so the feature required by its row faces forward.
Reward: Completes the skull display and reveals its associated clue.
Card Suit Grid
Hint: The suit determines the row, while the character's gaze, point, or orientation determines the column.
Solution: Place every heart tile in the heart row, diamonds in the diamond row, clubs in the club row, and spades in the spade row. Within each row, order the tiles by the direction shown at the top of the column: upward, vertical, neutral, left, right, and downward.
Reward: Completes the theatre classification mechanism.
Crew Location Pinboard
Hint: The board represents the submarine as it is now, not where people were during the murder.
Solution: Place every living crew member in the room where they are currently stationed. Put Magnus Mortuga's portrait outside the submarine diagram because he is no longer aboard as a living occupant.
Reward: Unlocks additional testimony and investigation topics.
Glowing Mushroom Catalog
Hint: Rotate the light source and count how many mushrooms of each species glow under the required condition.
Solution: Enter Dayglo 3, Evergleam 2, Illuminight 4, and Nevergleam 5.
Reward: Completes Mariana Moon's mushroom record.
Four Compasses
Hint: Each written clue describes how one compass should point in relation to the others.
Solution: Set the yellow compass in the upper-left to point left, the blue compass in the lower-left to point down, the pink compass in the upper-right to point toward roughly two o'clock, and the red compass in the lower-right to point toward the upper-left.
Reward: Repaired Compass
Diving Helmet Pipe Dials
Hint: Treat every pipe as a route carrying one symbol between two dials.
Solution: Begin with the central junction dials. Rotate each dial so the symbol leaving one pipe matches the symbol entering the next dial. Continue outward until every complete pipe route starts and ends with the same symbol.
Reward: Completes the diving-helmet mechanism.
Colored Orb Mechanism
Hint: The small displays are target patterns. The large orbs must reproduce them when the colored layers overlap.
Solution: Rotate the outer metal dials first to position the red groups, then rotate the inner glass orbs to align the white and pale spheres with the small reference displays. Confirm only when both large orbs reproduce their corresponding target arrangements.
Reward: Opens the Bilge mechanism and registers its evidence.
Pirates, Flags, and Lighthouses
Hint: Match each pirate to the flag sharing its visual pattern, while lighthouse pieces occupy the remaining color-coded positions.
Solution: Place the yellow lighthouse at the upper-left and the cyan lighthouse at the upper-right. Put the plain pale-yellow flag pirate between them on the left and the black-and-light-blue striped flag pirate between them on the right. Place the green-striped lighthouse at the lower-left and the red lighthouse at the lower-right. Match the remaining pirates to the red-and-white striped and black-white-green flags in the corresponding side and lower-center slots.
Reward: Completes the Dome Tank display.
Fill-in-the-Blank Deductions
Hint: The correct sentence must be supported by one specific clue, not merely by a suspicious statement.
Solution: Complete the sentence using the testimony established during interviews, then attach the physical evidence that directly proves it. When an answer fails, read Grimoire and Sally's expanded response to identify whether the incorrect part is the statement or the supporting clue.
Reward: Unlocks completed suspect conclusions and the final case sequence.
The Mermaid Mask Beginner Guide
Learn how exploration, questioning, 3D evidence, deductions, and the built-in hint system work before beginning the Mortuga case.
The investigation advances by finding evidence and then showing it to the right people. There is no need to guess the culprit early: search each room carefully, inspect every side of each object, and revisit the crew whenever the notebook gains a meaningful clue.
Follow the Core Investigation Loop
Every major section follows the same repeatable process.
- Explore every accessible room and inspect highlighted objects.
- Question the people in that area about all available topics.
- Present newly collected evidence to characters who may recognize it.
- Return to earlier rooms when a clue reveals a hidden compartment or new interaction.
- Use the resulting testimony and evidence in a personal investigation.
Use the Map Frequently
The submarine expands gradually, and old rooms regularly receive new interactions.
- Check every unlocked floor after a major conversation.
- Revisit the Parlor and crew quarters when an object appears to watch, blink, or react.
- Do not assume a completed room is permanently finished.
- Use room names in the notebook to track where unfinished evidence originated.
Exhaust Every Interview Topic
A character's useful dialogue is divided between personal questions, suspect questions, and evidence reactions.
- Ask every introductory question when meeting someone for the first time.
- Ask each person about every other crew member.
- Present clues even when the connection is not immediately obvious.
- Return after collecting photographs, letters, logs, recordings, or property documents.
- New suspicion topics appear after enough supporting evidence has been seen.
Inspect 3D Evidence Completely
Important clues are fully modeled objects that can hide information on their sides, back, base, or interior.
- Rotate each object through a full circle.
- Zoom in on seams, labels, symbols, switches, and damaged areas.
- Try opening lids, turning dials, moving parts, and reversing the object.
- Continue until all inspection hotspots have been acknowledged.
- Recheck an object when later testimony explains a symbol you previously ignored.
Read the Notebook Before Wandering
The notebook records important evidence, testimony, rooms, and active lines of inquiry.
- Look for subjects that still lack a conclusion.
- Compare a character's statement with the physical clues collected nearby.
- Use unresolved entries to decide which suspect should be revisited.
- Review the notebook after every multi-step puzzle or hidden-room discovery.
Build Deductions from Proof
Personal investigations combine a completed statement with the clue that proves it.
- Choose the sentence that directly follows from established testimony.
- Attach the most specific physical clue rather than a generally suspicious item.
- Separate motive, opportunity, and method instead of treating them as one conclusion.
- Read Grimoire and Sally's response after a failed attempt for an additional pointer.
Use Hints Without Penalty
The optional hint system can guide the next action or explain a puzzle without affecting completion.
- Open the first hint when the objective is unclear.
- Use deeper hints only after inspecting every part of the object.
- Check whether the hint refers to a room, a person, or a deduction clue.
- There is no score penalty for requesting help.
Recover from a Progression Block
Most apparent dead ends are caused by one unread clue reaction or an incompletely inspected object.
- Rotate every recent 3D clue again and check for missed hotspots.
- Present the newest evidence to all crew members with available dialogue.
- Return to the room where that evidence was discovered.
- Check the map for a newly opened floor or doorway.
- Complete any unfinished personal investigation shown in the notebook.
Avoid Accidental Story Spoilers
The case is designed so players can investigate freely without knowing the final solution.
- Use chapter- and room-specific hints instead of reading the ending route.
- Finish each suspect investigation before opening final-case material.
- Keep the final confrontation section collapsed until all normal dialogue is exhausted.
- Treat suspicious statements as leads rather than proof of guilt.
The Mermaid Mask Characters and Suspects
Meet Detective Grimoire, Sally, the murdered captain, and the eight eccentric people investigated aboard the Mortuga submarine.
Every crew member reacts to evidence and to the other suspects, making repeat interviews essential. These dossiers cover their public roles, relationships, testimony, investigative angles, and early evidence without naming the culprit or revealing the final solution.
Detective Grimoire
Lead detective and player-controlled investigatorLocation: Moves throughout the Mortuga submarine
Testimony: Grimoire builds the case by inspecting physical evidence, questioning the crew, and completing evidence-supported deductions.
Investigative angle: Not a suspect.
Key evidence
Sally Spears
Grimoire's sharp-tongued assistant and investigative partnerLocation: Travels with Grimoire
Testimony: Sally provides observations, challenges weak deductions, and gives increasingly specific feedback after unsuccessful puzzle or conclusion attempts.
Investigative angle: Not a suspect.
Key evidence
Magnus Mortuga
Murdered captain and owner of the Mortuga submarineLocation: Found dead in the Illusion Theatre
Testimony: Mortuga cannot testify, so his history must be reconstructed through his log, possessions, property records, and the statements of his crew.
Investigative angle: The victim's private dealings, ownership history, and relationships provide possible motives for several suspects.
Key evidence
Sinthia Seafoam
Acting captain and experienced nautical engineerLocation: Control Room
Testimony: Sinthia discusses the ship, Mortuga's command, her engineering background, the crew, and the responsibilities she inherited after his death.
Investigative angle: Her succession to command, concealed photograph, and connection to Mortuga's property history make her secrecy an important investigative angle.
Key evidence
Symmetry Silkmoth
Illusionist aboard the submarineLocation: Child's Room
Testimony: Symmetry answers questions about stagecraft, the crew, Mortuga, the strange newspaper story, the sail cloth, the illusion poster, and the Glass Eyeball.
Investigative angle: Her knowledge of illusions, concealed spaces, and visual deception makes her relevant to an apparently impossible locked-room murder.
Key evidence
Madam Tadpole
Self-described half-mermaid and resident of the Airlock GrottoLocation: Airlock Grotto
Testimony: Tadpole says she saw a glowing-eyed demon on the Fore Deck around the time of the murder and heard it speak what she describes as an alien language.
Investigative angle: Her access to the airlock, unusual account, and knowledge of activity outside the main rooms make her movements important to the timeline.
Key evidence
Dr. Zacharias Zephyr
Dream doctor and mystical researcherLocation: Dream Chamber
Testimony: Zephyr explains his dream practice, discusses Mortuga and the crew, and comments on the unusual devices kept in his chamber.
Investigative angle: His mysterious equipment, chemical bottles, and possible connection to unusual perceptions place his methods under scrutiny.
Key evidence
J.D. Wirman
Successful writer and author connected to The Hex of the HelmsmenLocation: Men's Bunk Room
Testimony: Wirman discusses his writing, his status aboard the ship, Mortuga, Dirk, and the other members of the crew.
Investigative angle: His secret correspondence and literary connection to the case's supernatural imagery raise questions about what he knew before the murder.
Key evidence
Dirk Dansom
Actor and energetic celebrity passengerLocation: Men's Bunk Room
Testimony: Dirk discusses his career, Mortuga, Wirman, and the rest of the crew. His locked phone contains private calls, messages, and emails.
Investigative angle: Private communications and a secretly recorded statement about killing someone to become free suggest that he was under personal pressure.
Key evidence
Mariana Moon
Historian and meticulous collector of informationLocation: Cargo Hold
Testimony: Mariana discusses Mortuga's history, the crew, her research, the Silkwirm material, and the objects stored in the Cargo Hold.
Investigative angle: Her hidden recordings show that she possessed information other suspects did not know she had, making her knowledge and timeline important.
Key evidence
Godrik "Mr" Gripp
Eccentric merchant and mechanical shopkeeperLocation: Engine Room
Testimony: Gripp discusses his merchandise, mechanical work, Mortuga, and the other crew members after Grimoire examines the items in his shop.
Investigative angle: His access to the submarine's mechanical systems and his work with damaged or altered objects create questions about means and opportunity.
Key evidence
The Mermaid Mask Clues and Evidence
Track the physical objects, documents, testimony, recordings, and environmental details needed to solve Captain Mortuga's locked-room murder.
Evidence aboard the Mortuga submarine often becomes useful only after it is fully examined and presented to the correct crew member. Use this table to find each clue, identify the suspects connected to it, and see whether it is required for progression or an optional investigation detail.
Case File
RequiredFound by: Open the red case folder before leaving the inn.
Examination: Read the locked-room murder summary and review the known facts about Magnus Mortuga's death.
Unlocks: Introduces the murder case and the initial investigation objective.
Linked suspects
The Hex of the Helmsmen
RequiredFound by: Inspect the book lying near Sally.
Examination: Read its supernatural maritime story and compare its imagery with later references to curses, masks, and the cauldron.
Unlocks: Provides thematic context for the apparent curse surrounding the murder.
Linked suspects
Unusual Green Light
RequiredFound by: Inspect the glowing area before the submarine surfaces.
Examination: Observe the color, location, and Sally's reaction to the light.
Unlocks: Advances the arrival sequence and introduces the submarine's unusual visual technology.
Linked suspects
Glowing Carved Buoy
Found by: Inspect the carved buoy immediately after boarding.
Examination: Rotate the view and compare its glowing details with later descriptions of lights seen outside the submarine.
Unlocks: Adds context to later Fore Deck testimony.
Linked suspects
Ragged Sail Cloth
RequiredFound by: Inspect the torn fabric near the stage and crime scene.
Examination: Check the damaged edges, material, and its connection to The Stargazing Girl display.
Unlocks: Supports questions about stage equipment, concealment, and movement inside the theatre.
Linked suspects
Upside-Down Illusion Poster
RequiredFound by: Inspect the theatre poster from both orientations.
Examination: Turn the image upside down and identify how its meaning changes when viewed differently.
Unlocks: Establishes visual deception as an important part of the case.
Linked suspects
Chalk Outline
RequiredFound by: Inspect every highlighted point around Mortuga's body position.
Examination: Compare the body's position with the cauldron, stage entrances, and nearby mechanisms.
Unlocks: Supports the first deduction about how the victim died.
Linked suspects
Stone Cauldron
RequiredFound by: Examine the ancient cauldron beside the chalk outline.
Examination: Inspect the lock, rim, interior, exterior symbols, base, and surrounding stage connections.
Unlocks: Allows Grimoire to conclude that Mortuga opened the cauldron and was killed by what emerged from or was concealed inside it.
Linked suspects
Lady of the Looking Glass Newspaper
RequiredFound by: Read both sides of the newspaper page.
Examination: Review the illusion story on the front and the sea-serpent report printed on the reverse.
Unlocks: Creates new interview topics concerning illusions and supposed sea creatures.
Linked suspects
Glass Eyeball
RequiredFound by: Complete the portrait-card and lens mechanism.
Examination: Rotate the glass eye and inspect its shape, iris, rear fitting, and mechanical edges.
Unlocks: Opens the eye-shaped lock on the Captain's Cabin.
Linked suspects
Submarine Blueprint
RequiredFound by: Inspect the plans displayed in the Control Room.
Examination: Review the submarine's floors, connected rooms, restricted sections, and possible movement routes.
Unlocks: Provides context for room access, machinery, and the crew-location investigation.
Linked suspects
Captain's Log
RequiredFound by: Solve the switchboard by connecting red 1 to 9, blue 3 to 11, and yellow 6 to 12.
Examination: Read Mortuga's entries and compare them with the crew's accounts of his recent actions.
Unlocks: Adds new questions about Mortuga's plans, command decisions, and private concerns.
Linked suspects
Gloomy Underwater Photograph
RequiredFound by: Open the pink pig safe and collect the concealed photograph.
Examination: Inspect the figures, setting, background, lighting, and any identifying features.
Unlocks: Creates new reactions from Sinthia and Symmetry and points toward another hidden item.
Linked suspects
Inn Deeds
RequiredFound by: Search beneath Sinthia's mattress after discussing the photograph with Symmetry.
Examination: Read the ownership names, property details, dates, and connections to Stonetop Inn.
Unlocks: Reveals a concealed financial and personal connection involving Mortuga.
Linked suspects
Dirk's Phone
RequiredFound by: Complete the matching-symbol channel puzzle.
Examination: Read every available call record, message, and email after unlocking the device.
Unlocks: Adds private statements and relationship details to Dirk's investigation.
Linked suspects
Letter from Ibis
RequiredFound by: Solve the rotating typewriter-ring mechanism.
Examination: Read the full handwritten message and inspect the signature, wording, and intended recipient.
Unlocks: Introduces a secret relationship and new questions about Wirman's knowledge before the murder.
Linked suspects
Hex Bottle
RequiredFound by: Inspect Zephyr's bottle collection and complete the cap-matching puzzle.
Examination: Rotate each bottle and compare its liquid, label, vapor, viscosity, and markings with the available caps.
Unlocks: Supports questions about altered perception, chemicals, dreams, and supernatural claims.
Linked suspects
Silkwirm Map
RequiredFound by: Search the stored sacks and materials in the Cargo Hold.
Examination: Inspect its routes, labels, symbols, and any locations connected to Mortuga's history.
Unlocks: Expands Mariana's historical testimony and the background of the submarine's voyage.
Linked suspects
Pipe-Shaped Dictaphone
RequiredFound by: Present the suspicious pipe-shaped object to Mariana after collecting the relevant mechanical evidence.
Examination: Identify its concealed recording function and play every stored conversation.
Unlocks: Reveals statements the speakers did not know had been recorded and creates new contradiction topics.
Linked suspects
Broken Handheld Radio
RequiredFound by: Open the Captain's Cabin with the Glass Eyeball and inspect Mortuga's table.
Examination: Rotate the radio, inspect its damaged casing, controls, antenna, and internal components.
Unlocks: Supports questions about communication, equipment damage, and Mortuga's final activities.
Linked suspects
Painting Titled Her
RequiredFound by: Inspect the framed painting in Mortuga's private room.
Examination: Study the depicted figure, title, frame, background, and Mortuga's reason for keeping it.
Unlocks: Adds personal context to Mortuga's past and the emotional meaning of the case.
Linked suspects
Repaired Compass
RequiredFound by: Solve the four-compass direction puzzle in Gripp's shop.
Examination: Inspect its casing, needle, repaired sections, and signs of previous damage or modification.
Unlocks: Creates additional reactions from characters who recognize the object or its origin.
Linked suspects
Diving Helmet
RequiredFound by: Inspect the helmet and complete its connected pipe-dial mechanism.
Examination: Rotate the helmet, trace each pipe route, and inspect the eye pieces, seals, and breathing components.
Unlocks: Provides context for the glowing-eyed figure reportedly seen on the Fore Deck.
Linked suspects
Crew Location Pinboard
RequiredFound by: Return after meeting every living crew member.
Examination: Place each person in their current room and position Mortuga outside the living-occupant layout.
Unlocks: Establishes the submarine's current population and opens additional personal investigations.
Linked suspects
The Mermaid Mask Achievements Guide
Plan a complete investigation, finish every important puzzle, inspect optional evidence, and earn all 21 Steam achievements with minimal cleanup.
The Steam release contains 21 achievements covering story progress, room puzzles, evidence inspection, interviews, and full-case completion. The descriptive achievement labels below identify each unlock route without exposing late-game revelations; hidden story achievements unlock naturally when the required investigation sequence is completed.
The Beginning
HiddenComplete the opening sequence at Stonetop Inn and begin the journey to the Mortuga submarine.
How to unlock: Read the Case File, inspect The Hex of the Helmsmen, wake Sally, and leave the inn.
Cleanup: Unlocks automatically during normal story progression.
All Aboard
HiddenBoard the Mortuga submarine after investigating the unusual light in Town Square.
How to unlock: Inspect the square, speak with Sally, wait for the submarine to surface, and enter from the Fore Deck.
Cleanup: Unlocks automatically before the first interior investigation.
Cabinet Cracker
Open the snake cabinet in the Mess Hall.
How to unlock: Treat each shape as its number of sides and enter the values 3, 9, 7, and 4 using the available shape combinations.
Cleanup: Required for story progression.
The Curse in the Cauldron
HiddenComplete the opening crime-scene deduction in the Illusion Theatre.
How to unlock: Inspect the chalk outline, ragged cloth, illusion poster, stage, and cauldron before confirming the first conclusion.
Cleanup: Unlocks automatically when Chapter One begins.
Eye for Detail
Complete the portrait-card and lens mechanism in the Child's Room.
How to unlock: Assemble the three girls, place Patricia in the center, resize the outer dolls, and use the fish-eye lenses on the outer faces.
Cleanup: Required to obtain the Glass Eyeball.
Switchboard Specialist
Restore the Control Room switchboard and recover the Captain's Log.
How to unlock: Connect the red cable from 1 to 9, blue from 3 to 11, and yellow from 6 to 12.
Cleanup: Required for the main investigation.
Safe and Sound
Open the pink pig safe in the Women's Bunk Room.
How to unlock: Arrange the branch values so the upper totals equal 8 and 6 and the lower connected totals equal 5, 9, and 2.
Cleanup: Complete it before finishing Sinthia's personal investigation.
Private Caller
MissableUnlock Dirk Dansom's phone and read its stored communications.
How to unlock: Rotate the channel tiles until every route connects matching endpoint symbols, then open all calls, messages, and emails.
Cleanup: Read every phone section before leaving the device interface.
Written in Code
Solve the typewriter-ring mechanism in the Men's Bunk Room.
How to unlock: Rotate the inner and outer rings until the five patterns follow the required 45-degree transformations.
Cleanup: Required to recover the letter addressed to Wirman.
Sweet Dreams
MissableComplete the bottle-cap puzzle in Dr. Zephyr's Dream Chamber.
How to unlock: Match the crescent, spade, bird-skull, sun, hand, and eye caps to the bottles described by their visible and physical properties.
Cleanup: Finish the mechanism while reviewing all Dream Chamber evidence.
Curiosity Satisfied
MissableComplete the skull classification display in the Cabinet of Curiosity.
How to unlock: Sort each skull by its ornament and facial feature, then rotate it so the required identifying feature faces forward.
Cleanup: Complete optional room mechanisms before entering the final confrontation.
Know Your Crew
Meet and question every primary suspect aboard the submarine.
How to unlock: Complete the initial interviews with Sinthia, Symmetry, Dirk, Wirman, Zephyr, Mariana, Gripp, and Madam Tadpole.
Cleanup: Ask every introductory topic when first meeting each character.
A Place for Everyone
Complete the crew-location pinboard in the Cargo Hold.
How to unlock: Place every living crew member in their current room and position Mortuga outside the submarine's living-occupant diagram.
Cleanup: Return to the board after all eight suspects have been introduced.
Recorded for Posterity
HiddenMissableIdentify Mariana Moon's disguised Dictaphone and listen to its recordings.
How to unlock: Present the pipe-shaped object with the relevant mechanical evidence, then play every available recorded conversation.
Cleanup: Listen to every recording before completing the related personal investigations.
True North
Repair the compass mechanism in the Engine Room.
How to unlock: Point yellow left, blue down, pink toward roughly two o'clock, and red toward the upper-left.
Cleanup: Collect the repaired compass and present it to characters with new reactions.
Deep-Sea Diver
MissableComplete the diving-helmet mechanism in the Airlock Grotto.
How to unlock: Rotate every connected dial so each pipe route begins and ends with the same symbol.
Cleanup: Finish it during Madam Tadpole's investigation rather than postponing it.
Evidence Collector
MissableRegister every required physical clue used by the main investigation.
How to unlock: Collect documents, photographs, recordings, mechanical objects, and crime-scene evidence from every accessible room.
Cleanup: Inspect each room again before the final sequence and verify that no required evidence entry remains incomplete.
Master Interrogator
MissableExhaust the important interview and evidence-reaction topics for the entire crew.
How to unlock: Ask each suspect about every crew member and present all major documents, photographs, recordings, and mechanical clues.
Cleanup: After every major discovery, revisit all characters showing unread dialogue indicators.
No Stone Unturned
MissableFully inspect the submarine's interactive rooms and three-dimensional evidence objects.
How to unlock: Rotate each object through every angle, activate all hotspots, and complete the optional mechanisms in rooms such as the Bilge, Dome Tank, and Cabinet of Curiosity.
Cleanup: Perform a complete room sweep before selecting the final-case confrontation.
Case Closed
HiddenComplete the final reconstruction of Captain Magnus Mortuga's murder.
How to unlock: Finish the required personal investigations, build the final timeline, and present the matching physical evidence during the confrontation.
Cleanup: Unlocks automatically when the main story is completed.
Perfect Investigation
HiddenMissableComplete the story while resolving the optional investigation content needed for full achievement completion.
How to unlock: Finish every required puzzle, complete optional room mechanisms, inspect all important evidence, and exhaust the significant crew reactions before closing the case.
Cleanup: Use a save made before the final confrontation to finish missed inspections or optional puzzles without replaying the full game.
The Mermaid Mask Ending Explained
Understand how the Illusion Theatre murder, the cauldron, the submarine's hidden mechanisms, and the crew's overlapping secrets fit into the final reconstruction.
The ending resolves the apparent supernatural curse by combining the evidence collected across the Mortuga submarine with the crew's hidden relationships and contradictory testimony. The sections below explain the logic of the final case while separating the murder method from the unrelated secrets that made several suspects appear guilty.
The Mermaid Mask Platforms and System Requirements
Compare the Steam, Nintendo Switch, Nintendo Switch 2, and PlayStation 5 releases before beginning the Mortuga submarine investigation.
The Mermaid Mask launched on July 16, 2026 as a single-player hand-drawn point-and-click murder mystery. The game supports 12 languages, contains 21 Steam achievements, and holds a 99% positive Steam user-review rating based on the supplied launch information.
PC via Steam
Release: 2026-07-16
Availability: Digital download through Steam
Format: Single-player point-and-click adventure
Controls: Mouse and keyboard for direct pointing, object rotation, dialogue selection, and puzzle interaction
Languages: 12 supported languages
Achievements: 21 Steam achievements
Review: 99% positive Steam user reviews based on the supplied launch information
Requirements: Exact processor, memory, graphics, operating-system, and storage values should be confirmed on the official Steam page before purchase.
Best for: Players who want Steam achievements, desktop controls, and direct mouse-based puzzle interaction.
Nintendo Switch
Release: 2026-07-16
Availability: Digital console release through Nintendo
Format: Portable and docked single-player adventure
Controls: Controller-based cursor movement, dialogue selection, object inspection, and puzzle interaction
Languages: 12 supported languages
Achievements: No Steam achievement integration
Review: Steam review percentage does not represent the Nintendo version
Requirements: No user-configurable hardware requirements; a compatible Nintendo Switch console and sufficient storage are required.
Best for: Players who prefer portable investigation sessions or television play from a standard Nintendo Switch.
Nintendo Switch 2
Release: 2026-07-16
Availability: Digital console release through Nintendo
Format: Single-player adventure playable on Nintendo Switch 2
Controls: Controller-based navigation and puzzle interaction
Languages: 12 supported languages
Achievements: No Steam achievement integration
Review: Steam review percentage does not represent the Nintendo version
Requirements: No PC-style minimum specifications; a Nintendo Switch 2 console and sufficient free storage are required.
Best for: Players using Nintendo's newer hardware who want a portable or docked version.
PlayStation 5
Release: 2026-07-16
Availability: Digital console release through PlayStation
Format: Single-player point-and-click adventure adapted for controller play
Controls: DualSense controller navigation for room exploration, conversations, evidence inspection, and puzzles
Languages: 12 supported languages
Achievements: Steam achievements are separate from any PlayStation trophy support
Review: Steam review percentage does not represent the PlayStation version
Requirements: A PlayStation 5 console, available storage, and an account able to access the PlayStation storefront are required.
Best for: Players who prefer television-based controller play on PlayStation hardware.
Release Information
Release: 2026-07-16
Availability: Released simultaneously across the listed PC and console platforms
Format: Detective Grimoire series murder-mystery adventure
Controls: Interface varies by platform, but all versions center on exploration, conversations, evidence rotation, and visual puzzles
Languages: 12 supported languages
Achievements: 21 achievements specifically confirmed for the Steam release
Review: 99% positive on Steam according to the supplied data
Requirements: Platform availability and storefront requirements may change after release.
Best for: Players comparing launch availability before choosing a storefront.
Language Support
Release: Available from launch
Availability: Included with supported digital versions
Format: Text-heavy detective adventure with dialogue, documents, clue descriptions, and deduction prompts
Controls: Language can be selected through the game's settings when supported
Languages: 12 supported languages
Achievements: Achievement requirements remain the same across languages
Review: Language quality and availability should be checked on the selected storefront
Requirements: No additional hardware is needed for language selection.
Best for: Players who need localized dialogue and investigation text.
PC Minimum Requirements
Release: Applicable to the Steam release
Availability: Displayed on the official Steam product page
Format: Hand-drawn 2D presentation combined with rotatable three-dimensional evidence objects
Controls: Mouse and keyboard
Languages: 12 supported languages
Achievements: Steam client required for Steam achievement tracking
Review: 99% positive Steam user reviews based on the supplied data
Requirements: Verified minimum operating system, CPU, RAM, GPU, DirectX, and storage values must be taken from the official Steam listing.
Best for: Players checking whether an older or lower-powered Windows computer can run the game.
Recommended PC Setup
Release: Applicable to the Steam release
Availability: Use the official Steam recommendations when published or updated
Format: Narrative adventure with detailed illustrated rooms, animation, sound, and interactive 3D clues
Controls: Mouse recommended for precise object inspection
Languages: 12 supported languages
Achievements: Steam account and client required
Review: Launch reception is highly positive on Steam according to the supplied information
Requirements: Use hardware meeting or exceeding the official recommended Steam specifications. Keep enough free storage for the installation and future patches.
Best for: Players who want smooth scene transitions and comfortable manipulation of detailed evidence objects.