The Mermaid Mask detective grimoire: Walkthrough & Case Solutions - Series

The Mermaid Mask detective grimoire: Walkthrough & Case Solutions

Solve the mysteries of the Mortuga submarine in The Mermaid Mask detective grimoire with our complete walkthrough, puzzle guides, and clue analysis.

2026-07-18
The Mermaid Mask Wiki Team
Quick Guide
  • Primary case: Solve the complex murder mystery of Captain Magnus Mortuga inside The Mermaid Mask detective grimoire campaign.
  • Critical clues: Search key rooms like the Illusion Theater, the Bunk Room, and the Bilge for hidden evidence.
  • Puzzle solutions: Align the serpent cabinet dials, solve the card lens layout, and decrypt Dirk Dansom's locked phone.
  • Suspect interrogation: Cross-reference testimonies from Dr. Zephyr, JD Worman, and Madame Tadpole to identify contradictions.

The Mermaid Mask detective grimoire Case Files

Embarking on your investigation in The Mermaid Mask detective grimoire requires a keen eye for environmental clues and a structured approach to interrogating the submarine's eccentric crew. The story begins at 4:00 AM at the Stone Top Inn on Silkworm on Sea, where Detective Grimoire and Sally find themselves drawn into a bizarre murder case aboard the Mortuga submarine. To help you navigate the early stages of this nautical mystery, we have compiled the ultimate progression route and puzzle solutions.

Before diving deep into the suspect files, it is crucial to understand the layout of the submarine and how the primary crime scene connects to the rest of the vessel. The victim, Captain Magnus Mortuga, was discovered alone in a locked room with his throat cut, yet no weapon was found inside. The only other notable feature of the room is an ancient stone cauldron with deep scratches on the inside, which had reportedly never been opened until the night of the crime.

Video Highlights:

  • Retrieve the paperback novel Hex of the Helmsman belonging to Sally at the Stone Top Inn.
  • Board the Mortuga Submarine and investigate the strange green light emitting from the foredeck buoy.
  • Search the Illusion Theater crime scene to find the stone cauldron and the broken purple bottle.
  • Solve the Serpent Cabinet puzzle in the mess hall to obtain the hidden vitamin D tablets.

To establish a solid foundation for your detective work, you should first map out the key rooms of the submarine. Use the table below to track where critical clues are located and when you can access them.

RoomKey Clues FoundAccess ConditionImportance
ParlorLarge "Her" painting, speakerOpen by defaultMedium
Mess HallSerpent cabinet, card tableOpen by defaultHigh
Illusion TheaterVictim body, stone cauldron, posterOpen by defaultCritical
Bunk RoomDirk's tuxedo, locked phone, suitcaseOpen by defaultHigh
BilgeBroken diving licenseRequires phone lightMedium
Dream ChamberDr. Zephyr, rare artifactsOpen by defaultHigh
Investigation Tip

Always inspect environmental objects thoroughly. Many items, such as the paperback novel and the broken bottles, feature interactive 3D models that can be rotated to reveal hidden markings or labels.

Suspect Interrogations & Alibi Analysis

To crack the case in The Mermaid Mask detective grimoire, you must carefully analyze the testimonies of the survivors. Each passenger has a unique background and a specific reason for being aboard the Mortuga submarine. By comparing their statements, you can identify critical timeline discrepancies and uncover what they are trying to hide.

The crew consists of a diverse group of individuals, ranging from a self-proclaimed dream doctor to a famous novelist. During your initial conversations, pay close attention to where each suspect claims to have been when the submarine experienced a sudden, violent tilt.

Dr. Zacharias Zephyr

  • Role: Dream Doctor
  • Location: Dream Chamber
  • Key Clue: Empty glass bottles and mysterious dream equipment.

JD Worman

  • Role: Famous Author
  • Location: Bunk Room
  • Key Clue: Discarded story drafts and typewriter noise.

Madame Tadpole

  • Role: Former Diver
  • Location: Airlock
  • Key Clue: Stolen leather mask and diving license.

By cross-referencing their statements, you can construct a timeline of the events leading up to the discovery of Captain Mortuga's body. Use the alibi grid below to track each suspect's movements and identify potential lies.

SuspectLocation During MurderClaimed ActivitySuspicious Behavior
Dr. ZephyrAirlock / Dream ChamberCollecting items from airlockClutching a glass bottle and leather bag
JD WormanMess Hall / Bunk RoomWriting next novelStared intensely at the crime scene
Dirk DansomBunk RoomSleeping / Checking watchSaw someone swimming outside the window
Madame TadpoleAirlock / BilgeInvestigating blood dripThrew a boat door at a glowing "demon"
Godric GripEngine Room / BilgeRepairing Cornelius KaneStood in the dark bilge listening to voices
Discrepancy Warning

Pay close attention to Madame Tadpole's statement. She claims she threw a boat door at a "demon" with glowing eyes and later retrieved a leather mask from the water, which was subsequently stolen from her airlock.

Step-by-Step Puzzle Solutions

Progression in The Mermaid Mask detective grimoire is frequently blocked by intricate mechanical puzzles. To gather all necessary evidence, you must unlock several secure compartments and decrypt personal items belonging to the suspects. Follow these step-by-step instructions to solve the primary puzzles encountered during the early investigation.

These puzzles require a combination of spatial reasoning, mathematical calculation, and careful observation of the surrounding environment. Make sure you have inspected all nearby notes and drawings before attempting to input the solutions.

1

Unlocking the Serpent Cabinet

Locate the metal serpent statue in the Mess Hall. Rotate the four dials to match the correct geometric shape and number values: the left dial must display 3, the middle-left 9, the middle-right 7, and the right dial 4. This opens the cabinet to reveal the brown glass bottle.

2

Solving the Card and Lens Box

In the Child's Room, interact with the wooden chest. Drag the six cards and four glass lenses into the correct slots. Match the overlapping symbols of the star and moon based on the sizes of the dolls in the clue. This unlocks the compartment containing the strange glass eye.

3

Decrypting Dirk's Tuxedo Phone

Examine the tuxedo hanging in the Bunk Room and retrieve the cell phone from the breast pocket. Drag the geometric pattern tiles into their corresponding slots on the screen grid. Make sure the curved lines sit in the top row and the straight diagonals overlap perfectly to unlock the device.

4

Calibrating the Specialty Compasses

Visit Godric Grip's shop in the Engine Room. Place the four distinct compasses into their correct slots. Identify the clock compass, the compass pointing away from others, and the blue compass reacting to its neighbor. Solving this reveals the hidden ocean map scroll.

Each of these puzzles yields a unique item or piece of information that is essential for advancing the narrative. The table below summarizes the requirements and rewards for each major puzzle.

Puzzle NameSubmarine LocationKey Items RequiredReward Earned
Serpent CabinetMess HallNone (Logic puzzle)Vitamin D Tablets
Wooden ChestChild's RoomSix cards, four lensesStrange Glass Eye
Locked Cell PhoneBunk Room (Tuxedo)None (Grid puzzle)Dirk's Message Logs
Specialty CompassesEngine Room ShopFour unique compassesHidden Ocean Map Scroll
Puzzle Reward

Unlocking Dirk's phone reveals crucial emails from his agent and messages indicating that someone was keeping a close eye on JD Worman's sluggish writing progress.

Evidence Analysis & Progression Checklist

To build a flawless case in The Mermaid Mask detective grimoire, you must systematically collect and analyze every piece of physical evidence scattered across the submarine. The lack of a bladed weapon in the locked room suggests a highly unconventional method of murder, or a secret exit that the culprit used to escape.

As you explore each room, make sure to interact with every highlighted object. Some clues may seem insignificant at first but will become vital when presenting your final deductions to the crew.

Crucial Evidence to Gather:

  • Read the initial Case File left on the bar of the Stone Top Inn
  • Retrieve the broken purple bottle with the moon icon from the theater floor
  • Examine the upside-down 'Lady of the Looking Glass' poster on the theater pipe
  • Acquire the torn and taped Ocean Rescue diving license from the Bilge
  • Examine the 'Her' mermaid painting in the Parlor
  • Extract the map scroll showing coordinates two miles from the coast

Each piece of evidence contains specific details that link it to a particular suspect or location. Use the table below to analyze the properties of each item and determine your next lead.

Evidence ItemDescriptionFound LocationPrimary Lead
Case FileLeather folder with victim photosStone Top InnIdentifies Captain Magnus Martuga
Broken BottleSmashed glass with purple liquidIllusion TheaterSubtle botanical scent, marked with moon
Upside-Down PosterSymmetry Silk Moth performance billIllusion TheaterMentions Uncle Gregory and crystal ball
Diving LicenseCut and taped rescue diver cardBilgeBelongs to Madame Tadpole (Tanya)
Map ScrollMap showing a red X in the oceanEngine RoomCoordinates marked for Magnus Mortuga
Evidence Hint

The broken bottle found near the victim's body contains a subtle botanical scent. Compare this with Dr. Zephyr's extensive collection of medicine bottles in the Dream Chamber to find a match.

Advanced Theories & FAQ

As the investigation deepens, several inconsistencies emerge between the physical state of the submarine and the testimonies of the survivors. The mysterious green light, the locked stone cauldron with deep scratches on the inside, and the sighting of a swimming figure outside the window all point to a grander conspiracy. Use this FAQ to resolve common blocks in your gameplay.

By analyzing these advanced elements, you can begin to piece together the true sequence of events. Keep a close eye on the physical relationships between the rooms to understand how the murderer could have slipped away unnoticed.

Q: How do I light up the dark Bilge room?

You cannot explore the Bilge in complete darkness. First, unlock Dirk's cell phone from the tuxedo in the Bunk Room, and use its built-in screen light to illuminate the room and find the dial switch.

Q: What is the significance of the stone cauldron in The Mermaid Mask detective grimoire?

The stone cauldron in The Mermaid Mask detective grimoire was found at the feet of the victim. Although reported to have never been unlocked, it was found open with deep scratch marks inside, suggesting something was released or hidden within.

Q: Where can I find the missing leather mask described by Madame Tadpole?

The leather mask was temporarily stored in the Airlock after Madame Tadpole retrieved it from the ocean. However, it was stolen before Detective Grimoire's arrival and must be searched for in other crew quarters.

Q: Who is Symmetry Silk Moth and where is she hiding?

Symmetry Silk Moth is a young illusionist whose poster is found in the Illusion Theater. Her room is decorated like a stage magician's parlor, and she appears to be hiding using elaborate mirror tricks and illusions.

Final Case Assessment

Keep cross-referencing the timeline. The sudden movement and tilt of the submarine experienced by Worman, Dirk, and Mariana is a vital clue that links the physical positioning of the ship to the exact moment of the crime.