Complete Walkthrough by Chapter

This is a full-spoiler route through The Mermaid Mask. The Case File—your notebook of clues, suspects, and deductions—eventually resembles a sailor’s coat pocket after a rough night: everything is in there, while the useful object lurks at the bottom. When progress stalls, inspect the newest 3D clue from every angle, use each visible moving part, and revisit the person linked to it.

The order below cuts down on backtracking, but it is not the only valid room order. Open investigation phases allow harmless variation. The bold trigger notes mark fixed actions that open rooms, confrontations, deductions, or chapter transitions. Unlisted scenery and comic observations are flavor unless they add a clue or conversation topic.

Prologue: The Beginning

Mandatory route

Stonetop Inn: Inspect The Hex of the Helmsmen, open the red Case File, and read the murder summary. Wake Sally, open the map, and travel to Town Square.
Town Square and Fore Deck: Speak to Sally and inspect the green light in the water. Select the surfaced Mortuga Submarine, board it, inspect the glowing Wooden Buoy, and enter through the hatch.
Parlor: Let Sally restore the light. Examine the blocked Control Room window and its warning note. The room remains locked, so use the map and descend to the Mess Hall.
Mess Hall: Inspect the snake cabinet. Each shape is worth its number of sides: set the four windows to triangle for 3, square plus pentagon for 9, triangle plus square for 7, and square for 4. Open the cabinet and collect the Sun Tablets. Unlock requirement: opening the cabinet adds the remaining Prologue rooms, including the Illusion Theatre, to the map.
Illusion Theatre: Inspect the upside-down Illusion Poster, wooden wall panel, broken stool, Moon Vial, blood, Sail Cloth, Stone Cauldron, and chalk outline. Connect the stool to Stonetop Inn. Selecting the outline begins the deduction, so leave it until the other crime-scene clues have been checked.

Reasoning: Mortuga was alone behind a locked bulkhead, but the cauldron had been opened and was scratched from within. Answer: Complete the sentence as Magnus Mortuga unlocked the cauldron and was killed by what was inside. When asked what stands out, rotate the cauldron and select the deep scratches inside. Chapter transition: confirming the scratches begins Chapter One.

Optional cleanup: Inspect the Town Square statue and the serpent attached to the Mess Hall cabinet for two parts of Silversnake Sleuth. Signs, cookware, and other comic scenery are not required for the deduction.

Chapter One: The Curse in the Cauldron

Mandatory route

Child’s Room: Read the Newspaper Page, inspect the portrait, and open the Wooden Chest. Arrange the six cards into three girl-and-doll pairs. Make the outer girls look toward the middle, place the small lens on the left doll and the large lens on the right doll, and leave the middle pair unchanged. Collect the Glass Eyeball.
Parlor, then Child’s Room: Select the watcher behind the Control Room window. Return to the blinking portrait and meet Symmetry Silkmoth. Complete her basic questions and the available Mortuga, Illusion Poster, Newspaper Page, Sail Cloth, Glass Eyeball, Stone Cauldron, Moon Vial, and Wooden Buoy topics. Control Room unlock: return to the watcher after Symmetry’s first interview.
Control Room: Meet Sinthia Seafoam. Inspect the Submarine Blueprint, Ship’s Wheel, Captain’s Jacket, and Command Contract. On the switchboard, connect the red triangle plugs to 1 and 12, the yellow circle plugs to 4 and 6, and the blue square plugs to 7 and 11. Take the Captain’s Logbook from the opened compartment. Finish Sinthia’s first interview, then return to Symmetry and ask about the Golden Locket. Bunk Room unlock: completing both sisters’ first interviews adds their shared room to the middle-left map slot.
Symmetry and Sinthia’s Bunk Room: Inspect the Movie Magazine, Family Photo, and pink Pig Safe. Set the hat right, left eye right, right eye forward, nose down, left cheek lit, and tongue out. Collect the Underwater Photo. Show it to both sisters, then return to the room and inspect beneath Sinthia’s mattress for the Inn Deeds.
Dream Chamber: Inspect the Hex Bottle, Dream Helmet, and Fog Ball. On the perfume shelf, arrange the caps from left to right as arrow, bird skull, moon, hand, eye, and sun. Inspect the opened bookcase and collect the Caretaker’s Journal. Complete Dr. Zacharias Zephyr’s available interview topics.
Dirk and Wirman’s Bunk Room: Inspect the Action Figure and find Dirk’s Cellphone in the tuxedo. Complete its crossing symbol grid, then read the calls, messages, emails, and contacts needed later. Solve Wirman’s Typewriter by placing the open circle at 12 o’clock, diamond at 3, T symbol at 5, and closed circle at 6. Collect the Handwritten Letter and question Dirk Dansom and J.D. Wirman.
Engine Room: Inspect the Broken Compass and Compass Panel. Place yellow upper-left, purple lower-left, pink upper-right, and red lower-right, then collect the Ocean Map from the crate. Select shop items or leave the sales pitch three times to unlock normal questions with Godrik Gripp. Discuss Mortuga, the crew, the Ship’s Wheel, Ocean Map, and Broken Compass.
Cargo Hold: Meet Mariana Moon. Inspect the Silkwirm Map, her pipe, tent, and Pin Board, then finish her first interview. Place each living character in their current room, place Grimoire and Sally with Mariana, and put Mortuga outside the submarine diagram. After completing the board, inspect behind it for the Moon Photo. Illusion Theatre panel trigger: Mariana’s first interview directs the investigation back to the theatre; finish Wirman’s Illusion Poster topic as well if that clue reaction remains unread.
Illusion Theatre revisit: Open the wooden panel left of the cauldron. Arrange hearts, diamonds, clubs, and spades in their matching rows; the six columns face up, top-halves mirrored, bottom-halves mirrored, left, right, and upside down. Inspect the Lifesize Doll, lift its locket, open its flap, and take the Film Projector. Watch the first reel, then ask Symmetry about the doll and projector. Cornelius Cane unlock: this conversation adds the Cane topic when you next question Gripp.
Airlock Grotto: Meet Madam Tadpole. Inspect the Message in a Bottle, treasure chest, and Diving Helmet. Rotate the helmet’s dials until every connected pipe meets the same symbol, then collect the locked Pocketbook. Ask Tadpole about it, return to Dirk, and ask him to open it with Tadpole’s birthday. Read its photographs and other contents.
Bilge: Select Dirk’s Cellphone as the light source. Keep interacting near the right-hand switch until Sally reveals the mechanism. Move and rotate the two orbs so the left dial matches the upper target and the right dial matches the lower target. Restore the light and collect the Strange Device and Diving License.
Captain’s Cabin: Select the locked room at the far right of the upper map row and use the Eyeball Key made from the Glass Eyeball. Inspect the Handheld Radio, Ship in a Bottle, Iron Bell, and HER Painting. Ask Sinthia about the HER Painting, return, and rotate the sun above the painted woman to reveal the ladder.
Captain’s Quarters: Inspect the curtain, Model Town, and Black Box. Starting at the II marker, set the boat route to up 3, down-right 2, down 2, right 7, up-left 5, left 2, down-right 4, up-right 2, and left 5. Open the lighthouse, take the second film reel, and watch it with the Film Projector. Finally, inspect the Black Box and test its movable parts. Chapter transition: confirming that the Black Box cannot yet be opened begins Chapter Two.

Optional cleanup: Open the Golden Locket, read every Movie Magazine page and Cellphone screen, pull both Control Room levers, ask Sinthia about the Case File, remove the bandage from Cornelius Cane after receiving it, and inspect the dark bookcase gap in the Dream Chamber. These achievement actions do not replace required evidence conversations.

Chapter Two: The Box That Would Not Open

The Case File now looks like an evidence buffet arranged by a mildly hostile octopus. Do not present every object to everybody. Finish the clue reaction tied to each suspect, then clear that suspect’s Suspicion confrontation while the evidence is fresh.

Prepare the required evidence

Engine Room: Ask Gripp about Cornelius Cane, keep it as evidence, and inspect the portrait on his basket. Ask about the Ocean Map, then turn the map over and inspect its service-record label.
Airlock Grotto: Collect the Message in a Bottle if you skipped it. Ask Tadpole and the relevant suspects about it. The bottle remains sealed until the crew leaves their rooms later.
Cargo Hold: Inspect Mariana’s pipe and use its controls to expose the concealed Dictaphone. Listen to every available recording. Continue checking it when a later tape is found.
Evidence circuit: Finish the reactions linking the Film Projector and Lifesize Doll to Symmetry; Cellphone and Strange Device to Dirk; Handwritten Letter and Message in a Bottle to Wirman; Underwater Photo and Inn Deeds to Sinthia; Dictaphone to Mariana; Cornelius Cane and Ocean Map to Gripp; and Pocketbook, Diving License, and Moon Photo to Tadpole.

Required Suspicion conversations

Character-revelation warning: These confrontations expose private histories and false testimony, but not the culprit. Their order can vary once the matching Suspicion tabs appear. Completing all eight is the fixed advancement requirement.

Dr. Zephyr — Dream Chamber: Use the Moon Vial, Hex Bottle, Dream Helmet, Fog Ball, Caretaker’s Journal, Newspaper Page, Dictaphone recording, and Ship in a Bottle. Complete the full dream-experiment confrontation.
Symmetry Silkmoth — Child’s Room: Use the Lifesize Doll, Illusion Poster, Sail Cloth, Film Projector, Action Figure, and Dictaphone recording. Finish the reconstruction of The Stargazing Girl and the doll double.
Dirk Dansom — Bunk Room: Play Dictaphone recording 2, then use the Action Figure, Cellphone, Strange Device, Movie Magazine, and the fictional Markus Mordoom to explain who Dirk wanted to kill and why.
Godrik Gripp — Engine Room: Compare Cornelius Cane with the basket portrait and Ship’s Wheel. Use the Ocean Map service record, second film reel, Ship in a Bottle, and Wooden Buoy to finish the earlier-voyage questions.
Mariana Moon — Cargo Hold: Use the disguised Dictaphone, Pocketbook, Dirk’s Cellphone records, Black Box, Silkwirm Map, and Handheld Radio. Complete the chain showing why she brought the box aboard.
Sinthia Seafoam — Control Room: Use the Command Contract, Wirman’s Typewriter, Captain’s Logbook, Family Photo, Submarine Blueprint, and Inn Deeds. Finish the questions about the contract, signature, and submarine ownership.
J.D. Wirman — Bunk Room: Use the Handwritten Letter, Newspaper Page, The Hex of the Helmsmen, Message in a Bottle, and Typewriter. Finish the discussion of Ibis and Wirman’s planned book.
Madam Tadpole — Airlock Grotto: Use Dictaphone recording 1, Pocketbook, Diving License, Moon Photo, and Illusion Poster. Finish the questions about the Pocketbook’s former owner and Tadpole’s argument with Mortuga.

Fixed advancement trigger: After all eight Suspicion conversations, report to Sinthia in the Control Room. She gathers everyone in the Mess Hall and resurfaces the submarine. Go to the Fore Deck, pull the right-hand lever, and finish the Sally conversation. This clears the crew from their rooms and unlocks the Aft Deck and Dome Tank.

Late investigation route

Aft Deck: Collect the large Figurehead, then open the map to trigger Grimoire and Sally’s strange voice exchange.
Dome Tank: Solve the pirate, flag, and lighthouse chest, then collect the Ocean Treasure.
Control Room: With Sinthia absent, solve the nine-piece Electronic Panel beside the Captain’s Jacket. Open the jacket and take the second Handheld Radio to reunite the pair.
Airlock Grotto: Use Wirman’s Typewriter to break the Message in a Bottle. Read the message and turn the paper over to reveal the missing second page of the Command Contract.
Cargo Hold: Enter Mariana’s tent and solve the Mushroom Puzzle Box. Take the second Dictaphone tape and listen to all four recordings. Black Box unlock: the last recording explains the handle movement.
Captain’s Quarters: Inspect the Black Box, replay the final recording when prompted, and drag its handle. Collect the Mourning Envelope, third film reel, and Torn Scroll. Watch the third reel.
Dream Chamber and Cabinet of Curiosities: Select the face in the bookcase gap while Zephyr is absent. Enter the hidden Cabinet of Curiosities, solve the skull shelf, take The Mermaid’s Tongue, and read both of Zephyr’s Letters. Back in the Dream Chamber, inspect the Hex Bottle. After Symmetry taps it three times, inspect it again to see Mortuga and the Iron Bell.
Captain’s Cabin: Inspect the Iron Bell and connect its hanging part to the matching shape on the Stone Cauldron’s lid. Move the table, lift the rug, and open the hatch to the Illusion Theatre.
Illusion Theatre: Close the Stone Cauldron. Inspect the Illusion Poster and rotate its loose pipe to lower the Iron Bell. Try the left and right handles, then let Sally help turn them together. Inspect the Metal Fragment lodged in the mechanism.

Deduction trigger: Complete both reconstruction branches. In A Murderer, identify the Iron Bell, use the Hex Bottle vision, state that Mortuga operated it himself, and connect the Metal Fragment, Mourning Envelope imprint, HER Painting, Figurehead, and final Dictaphone recording. In And a Thief, use the Captain’s Cabin hatch, Eyeball Key, Bilge vent, Ship’s Wheel, Moon Vial and missing dropper, Captain’s Logbook, and the angle of Mortuga’s blood. Completing both sends you to the group confrontation in the Parlor.

Major spoiler: final confrontation and culprit

Parlor: Speak to Sinthia. Present The Mermaid’s Tongue, use page 5 of the Caretaker’s Journal to explain it, and present the Underwater Photo.
Connect the Ocean Map to the Torn Scroll. Select the coral and gemstone eyes on the Ocean Treasure, then state that Mortuga kept the mask hidden. These details explain the scratches inside the cauldron and what was stolen.
To prove a third person sailed aboard the Dearest Selena, use Mortuga’s second film reel and select the figure peeking from the doorway. Add the recording of Mortuga speaking to an unseen traveler, the Handheld Radios, and the rattling Ship in a Bottle.
Compare the Ship in a Bottle with the Model Town. Select Godrik Gripp as the person missing from the town, use the Ocean Map’s service-record label to connect him to the voyage, and break the bottle to reveal his hidden model.
State that Gripp still has both the weapon and key. Inspect the Broken Compass and open it to reveal the other half of Felicia’s necklace. Chapter transition: exposing this evidence identifies Gripp and begins Chapter Three.

Optional cleanup: Watch all three Film Projector reels, read both Zephyr letters fully, inspect the Boggy head in the Cabinet of Curiosities, and finish any remaining clue pages or object controls before starting the Parlor confrontation.

Chapter Three: The Wayward Navigator

Ending spoiler warning: This chapter exposes the culprit, motive, method, and fate of the submarine.

Full Chapter Three route and ending

Dearest Selena voyage: Advance Gripp’s account. Use the Ocean Map, Iron Bell, Mermaid’s Tongue, Ship’s Wheel, and Cornelius Cane when their parts of the voyage are questioned.
Creation of the Mortuga Submarine: Continue through Gripp’s return to Silkwirm, Mortuga’s claim about Felicia, the Inn Deeds, and the submarine’s construction.
A Gathering of Hapless Travelers: Arrange the eight character cards: Sinthia came to reclaim the submarine and later forged Mortuga’s signature; Wirman followed a letter with access instructions and considered using the murder for his book; Dirk was sent to watch Wirman and tried to persuade him to kill Markus Mordoom; Mariana was hired to research Felicia and brought Mortuga the Black Box; Gripp commissioned the submarine to search for The Mermaid’s Tongue and was present when Mortuga opened the Black Box; Zephyr was asked to smuggle The Mermaid’s Tongue aboard and hid it in the Cabinet of Curiosities; Symmetry was invited to work with Zephyr and performed The Stargazing Girl; Tadpole was rescued by Mortuga and offered to relieve him of the captaincy.
Correct the four misconceptions: For Tadpole, choose Godrik Gripp and Felicia Stonetop. For Sinthia, choose the Command Contract, its second page from the Message in a Bottle, and the Inn Deeds. For Wirman, choose the Handwritten Letter, Magnus Mortuga as its author, and Felicia Stonetop as the person he hoped Wirman knew about. For Symmetry, choose The Stargazing Girl, the Mourning Envelope, and Felicia Stonetop.
Murder account: Advance Gripp’s explanation of the necklace key and Mortuga’s lie. When asked why Mortuga opened the cauldron, choose he wanted to hide The Mermaid’s Tongue somewhere else.
Captain’s Quarters: After Gripp takes The Mermaid’s Tongue, follow him upstairs. Inspect the Fixed Compass he drops, then select the locked outer door and watch the Fore Deck sequence.
Control Room: Rejoin the crew after the submarine is pulled underwater. When Sinthia cannot find the route home, present the Fixed Compass.
Town Square: Speak to every gathered character. Completing all farewell conversations starts the final scene and credits.

Optional ending cleanup: Before presenting the Fixed Compass, rotate it and read its service-record label for Cost: Waived.

← Prev Next →