The Mermaid Mask: Complete Walkthrough Guide

This The Mermaid Mask walkthrough guides you through the investigation step by step. It covers important clues, suspect interviews, puzzle solutions, missable achievements, and the correct route through the Mortuga Submarine.

The game allows some rooms to be explored in different orders. This guide follows a simple route that reduces unnecessary backtracking and makes it clear where you should go next.

Guide status: This walkthrough will continue to be expanded toward 100% completion as additional chapters and verified solutions become available.

Prefer to solve the puzzles yourself? Visit our All Puzzle Solutions for progressive clues that help you reach each answer without immediately revealing the full solution.

The Mermaid Mask Prologue Walkthrough

The Prologue introduces the investigation system and takes Detective Grimoire and Sally from Stonetop Inn to the room where Magnus Mortuga’s body was discovered.

Stonetop Inn

The game begins inside Stonetop Inn, where Sally is sleeping nearby. Examine the room before trying to leave.

1. Examine the book beside Sally.
2. Inspect the bar stools.
3. Open and read the red Case File on the bar.
4. Interact with Sally after examining the Case File.

The Case File explains the unusual circumstances surrounding Magnus Mortuga’s death. After reading it, a green light becomes visible outside.

Open the map using the button in the lower-left corner and select the newly available location.

Next: Travel to the Town Square.

Town Square

Explore the abandoned Town Square and inspect the surrounding signs and objects. The main progression point is located at the end of the dock.

1. Examine the Town Square statue.
2. Walk to the end of the dock.
3. Select the green light in the water.
4. Select the submarine when it appears.

Next: Board the Mortuga Submarine and explore the Fore Deck.

Mortuga Submarine: Fore Deck

Inspect the important objects on the Fore Deck before entering the submarine.

• Wooden Buoy
• Rowboat
• Yellow writing
• Open doorway

The Wooden Buoy is especially important because its glowing carved eyes drew Grimoire and Sally toward the submarine.

Use the open doorway and descend into the submarine.

Next: Continue down the ladder into the Parlor.

Parlor

After Sally activates the submarine’s lighting, examine the Parlor.

• Examine the HER Painting above the fireplace.
• Inspect the Control Room doorway.
• Read the note covering the window in the door.

The Control Room is locked and cannot be entered yet. Open the map after inspecting the note.

Next: Travel one floor down to the Mess Hall.

Mess Hall

Explore the Mess Hall and inspect the snake-shaped cabinet on the left. Select Look Closer to begin the dial puzzle.

Mess Hall Snake Cabinet Puzzle Solution

The four numbered windows must contain shapes whose total number of sides matches the number shown.

Window	Correct Shape Combination
3	Triangle
9	Square + Pentagon
7	Square + Triangle
4	Square

Rotate the four dials until the correct shapes appear in every window, then press the lock button in the upper-right corner.

The cabinet opens after the correct combination is entered. Collect the Sun Tablets.

Next: Open the map and travel to the Illusion Theatre.

Illusion Theatre

The Illusion Theatre is the crime scene. Examine the entire room before interacting with the body outline.

• Upside-down poster
• Panel in the wall
• Knocked-over stool
• Broken Moon Vial
• Blood
• Banner
• Sail cloth or tapestry
• Stone Cauldron
• Body outline

When examining the knocked-over stool, select Stonetop Inn as the place where you previously saw the same type of stool.

After examining the other crime-scene objects, select the body outline to begin the first deduction.

Illusion Theatre Cauldron Deduction Solution

Complete the deduction using the following sentence:

Magnus Mortuga unlocked the cauldron and was killed by what was inside.

After completing the deduction, the game asks what stands out inside the cauldron. Rotate the cauldron and select the scratches.

Completing the deduction ends the Prologue and begins Chapter One.

The Mermaid Mask Chapter One Walkthrough

Chapter One opens several new areas of the submarine. The route below introduces the available suspects and clues in a clear order.

Child’s Room

From the Illusion Theatre, travel to the Child’s Room beside it.

• Read the Newspaper Page.
• Examine the girl portrait.
• Inspect the Wooden Chest.

Child’s Room Wooden Chest Puzzle Solution

1. Arrange the six cards into three vertical girl-and-doll pictures.
2. Place an eye lens over the left girl so she looks toward the middle.
3. Place the other eye lens over the right girl so she looks toward the middle.
4. Place the small lens on the left girl’s doll.
5. Place the large lens on the right girl’s doll.
6. Do not place a lens on the middle girl or her doll.
7. Press the lock button in the upper-right corner.

Collect the Glass Eyeball from inside the chest.

Next: Return to the Parlor.

Parlor Revisit

A face is now visible through the Control Room window. Select it and speak with the person inside.

You will be told to speak with Symmetry in the Child’s Room. Return there and interact with the girl standing in the frame.

Questioning Symmetry

Speak with Symmetry and work through the following topics.

Basics

• Yourself
• The Mortuga Submarine
• Night of the Murder

Suspects

• Symmetry
• Magnus Mortuga

Clues

• HER Painting
• Illusion Poster
• Newspaper Page
• Sail Cloth
• Glass Eyeball
• Stone Cauldron
• Moon Vial
• Wooden Buoy

Any available answer can be selected during the optional symbolic response questions.

Next: Return to the Parlor and speak through the Control Room window again.

Control Room

The person behind the door now allows you to enter the Control Room. Examine the room before leaving.

• Submarine Blueprint
• Ship’s Wheel
• Captain’s Jacket
• Command Contract
• Control Panel

Control Room Wires Puzzle Solution

Select the wires in the lower-right section of the Control Panel and connect the six plugs to the following sockets:

Wire Pair	Correct Sockets
Red Triangle	1 and 12
Yellow Circle	4 and 6
Blue Square	7 and 11

The compartment opens after all six plugs are connected correctly. Collect the Captain’s Logbook.

Questioning Sinthia

The person inside the Control Room is Sinthia Seafoam. Ask her about the following subjects.

Basics

• Yourself
• The Mortuga Submarine
• Night of the Murder

Suspects

• Magnus Mortuga
• Symmetry
• Sinthia

Clues

• Command Contract
• Captain’s Jacket
• Captain’s Logbook
• Ship’s Wheel
• Glass Eyeball
• Stone Cauldron
• HER Painting
• Wooden Buoy
• Case File

After completing Sinthia’s first interview, return to Symmetry and ask about the locket around her neck.

Opening the Golden Locket

1. Ask Symmetry about the Golden Locket.
2. Inspect the locket.
3. Select the Open option.
4. Examine its contents.

After the first interviews with Symmetry and Sinthia, their shared Bunk Room becomes available.

Next: Travel to Symmetry and Sinthia’s Bunk Room on the far-left side of the middle row.

Symmetry and Sinthia’s Bunk Room

• Read the Movie Magazine.
• Examine the Family Photo.
• Inspect the Piggy Bank.

Piggy Bank Puzzle Solution

Move the Piggy Bank’s features into the following positions:

• Hat pointing to the right
• Left eye pointing to the right
• Right eye pointing forward
• Nose pointing downward
• Left cheek illuminated
• Tongue sticking out

Rotate the pig and confirm that the white values match the fixed red totals in every row and column.

Collect the Underwater Photo after the Piggy Bank opens.

Follow-Up Interviews

• Ask Sinthia about the Family Photo, Underwater Photo, and Golden Locket.
• Ask Symmetry about the Underwater Photo and Sinthia.

After speaking with Symmetry again, return to the Bunk Room and inspect underneath Sinthia’s mattress. Collect the Inn Deeds.

Next: Visit Dirk and Wirman’s Bunk Room.

Dirk and Wirman’s Bunk Room

Meet Dirk Dansom and J.D. Wirman, then inspect the room.

• Action Figure
• Cellphone inside the tuxedo pocket
• Wirman’s Typewriter

Dirk’s Cellphone Puzzle Solution

A Across

1. <
2. Backward L turned on its side
3. V
4. >
5. Straight line

B Down

1. Backward L
2. /
3. <

C Down

1. U
2. ^
3. V

D Down

1. Upside-down U
2. L turned on its side
3. Straight line

Wirman’s Typewriter Puzzle Solution

The symbols on the paper are the same basic shapes rotated in 45-degree steps. Set the middle symbol in each sequence to the missing rotation between the symbols on its left and right.

Use the image below to copy the exact final position of all three dials.

Read the handwritten letter addressed to Wirman from Ibis after solving the puzzle.

Question Dirk About

• Yourself
• Mortuga Submarine
• Night of the Murder
• Mortuga
• Symmetry
• Dirk
• Sinthia
• Zephyr
• Cellphone
• Action Figure
• Underwater Photo
• Sun Tablets
• HER Painting
• Movie Magazine
• Hex of the Helmsman
• Stone Cauldron

Question Wirman About

• Yourself
• Mortuga Submarine
• Night of the Murder
• Mortuga
• Symmetry
• Dirk
• Sinthia
• Zephyr
• Wirman
• Action Figure
• Underwater Photo
• HER Painting
• Movie Magazine
• Hex of the Helmsman
• Stone Cauldron
• Newspaper Page
• Illusion Poster

Next: Travel to the Dream Chamber.

Dream Chamber

Meet Zacharias Zephyr and inspect the important objects in the room.

• Hex Bottle
• Dream Helmet
• Fog Ball
• Bottle shelves
• Bookcase above the bottles

Dream Chamber Bottle Puzzle Solution

Arrange the bottle lids in the following order from left to right:

1. Arrow
2. Bird Skull
3. Moon
4. Hand
5. Eye
6. Sun

After the glass panel opens, inspect the bookcase directly above it and collect the Caretaker’s Journal.

Question Zephyr About

• Yourself
• The Mortuga Submarine
• Night of the Murder
• Mortuga
• Symmetry
• Sinthia
• Zephyr
• HER Painting
• Underwater Photo
• Stone Cauldron
• Moon Vial
• Wooden Buoy
• Newspaper Page
• Glass Eyeball
• Sail Cloth
• Caretaker’s Journal
• Hex Bottle
• Dream Helmet
• Fog Ball

Next: Travel to the Cargo Hold.

Cargo Hold

Meet Mariana Moon and work through every available question about herself, the submarine, the murder, the suspects, and the clues you have collected.

• Search the bags on the left.
• Collect the Silkwirm Map.
• Inspect the pinboard on the right.
• Question Mariana about every available subject.

The pinboard may not be solvable immediately if you have not met every crew member. Return after completing the remaining interviews.

Next: Unlock the Captain’s Cabin when the Glass Eyeball interaction becomes available.

Captain’s Cabin

Use the Glass Eyeball on the locked Captain’s Cabin.

• Inspect the chest with the eyes.
• Collect the Handheld Radio.
• Collect the bell on the table.
• Inspect the ship in a bottle.
• Examine the HER Painting.

Next: Travel to the Engine Room.

Engine Room

Meet Mr. Gripp inside the hanging basket and examine the room.

• Broken Compass
• Compass Panel
• Mr. Gripp

Select several items offered by Gripp until the questioning menu becomes available. Ask him about every available basic, suspect, and clue topic.

Engine Room Compass Puzzle Solution

Position	Compass
Top left	Yellow
Bottom left	Purple
Top right	Pink
Bottom right	Red

After the panel unlocks, inspect the opened compartment or crate and collect every clue revealed inside.

After questioning Gripp, Sally points out that there may be more to Mariana’s wooden pipe.

Next: Return to the Cargo Hold.

Cargo Hold Revisit

Return to Mariana and investigate her wooden pipe. It is a hidden recording device rather than an ordinary pipe.

Listen to the available recording and question Mariana about the new information.

Cargo Hold Pinboard Puzzle Solution

Place every living character in the room where they are currently located. Place Magnus Mortuga outside the submarine map.

Next: Visit the Airlock Grotto.

Airlock Grotto

Meet Madam Tadpole and complete every available conversation.

1. Ask about herself.
2. Ask about the Mortuga Submarine.
3. Ask about the night of the murder.
4. Work through every available suspect topic.
5. Show her every clue that unlocks a new conversation.

Tadpole describes seeing a strange figure on the Fore Deck during the night of the murder. Its eyes appeared to glow, and it seemed to communicate in an unfamiliar language.

Finish every available topic before leaving the room.

Next: Return to the Illusion Theatre.

Illusion Theatre Revisit

Return to the Illusion Theatre and inspect the suspicious wall panel on the left side of the room.

1. Select the wall panel.
2. Push or open it when the interaction becomes available.
3. Inspect the secret mechanism behind the wall.

The hidden wall puzzle becomes visible here, but the verified route does not require you to solve it immediately. Continue collecting testimony and clues when the game directs you to another room.

Achievement Checklist

Achievement	Requirement
Silversnake Sleuth	Examine the Town Square statue, Mess Hall statue, Newspaper Page, and Family Photo
Lever Lover	Pull both levers on the Control Room panel
Tangle Tower	Ask Sinthia about the Case File
A Witch of Some Infamy	Open Symmetry’s Golden Locket
Break Time	Read every page of the Movie Magazine
Prying Eyes	Inspect everything on Dirk’s Cellphone
Who’s There…?	Examine the dark hole in Zephyr’s bookcase

What to Do If You Get Stuck

• Open the map and look for a magnifying-glass marker over a room.
• Return to previously questioned suspects after collecting a new clue.
• Ask every character about newly unlocked suspects and evidence.
• Rotate clue objects and inspect them from every available angle.
• Read every page of magazines, files, journals, and phone menus.
• Revisit the Illusion Theatre when new crime-scene interactions become available.

This walkthrough will be updated with additional rooms, deductions, puzzle solutions, clues, and achievement requirements as the remaining chapters are fully verified.