Submarine Exploration Walkthrough

Once the prologue concludes, Detective Grimoire and Sally Spears board the Mortuga Submarine—the primary crime scene and the bulk of The Mermaid Mask's twelve-hour runtime. This walkthrough covers the first major exploration phase before structured crew interviews dominate the middle act. The Mortuga is a labyrinth of interconnected rooms spanning eleven distinct locations from the social Parlor to the industrial Engine Room. Expect roughly half of the game's fifty clues to appear in this phase, many requiring 3D inspection or environmental manipulation. Move methodically: the game rewards backtracking with newly unlocked dialogue and puzzle states rather than punishing you with fail states.

Meeting the Crew Aboard Mortuga

Your first stop after descending the gangway is the Parlor, where several voiced suspects congregate between duty shifts. All eight fully voiced suspects—Symmetry Silkmoth, Dirk Dansom, JD Wirman, Zacharias Zephyr, Madam Tadpole, Godrik Gripp, Mariana Moon, and Captain Seafoam—can be encountered during this exploration block, though not every character is present in the Parlor simultaneously. Introduce every conversation topic flagged with a question mark; topics evolve as you discover physical evidence elsewhere on the ship. Spears maintains a running commentary that often hints when a suspect's statement contradicts an object you have already collected.

Before interrogating aggressively, prioritize passive observation. Each suspect animates distinct idle behaviors—Zephyr calibrates pocket instruments, Gripp polishes brass fittings, Moon sketches in a waterproof journal—that reinforce personality profiles used later in the Suspicion Tracker. Avoid presenting evidence prematurely; the game's investigation system unlocks formal accusation mechanics only after you complete baseline exploration milestones in the Mess Hall, Control Room, and Child's Room. If you are achievement hunting, speak to every suspect at least twice before entering the Illusion Theatre crime scene proper.

Child's Room Investigation

The Child's Room is one of the Mortuga's most emotionally charged spaces and a mechanical hub for several mid-game puzzles. Decorated with nautical toys, chalkboard diagrams, and a miniature submarine playset, the room connects narratively to Mortuga's family history without relying on cheap twists. Search the toy chest, bunk nook, and porthole alcove for three inspectable clues that automatically annotate your Evidence Checklist. One clue—a set of magnetic fridge letters—directly foreshadows the piggy bank numbers puzzle found later in the Bunk Rooms corridor.

The Child's Room also houses an optional audio log that updates the map legend for adjacent Dream Chamber access. Dream Chamber doors remain locked until you solve the shape matching lock on the corridor safe, so note Spears' reminder about "four pieces that look alike but aren't." Players on PlayStation 5 can use the touchpad for rapid hotspot cycling in this cramped space, while PC players may prefer mouse-driven precision for the paper boat origami inspection sequence.

Control Room and Navigation Systems

The Control Room sits aft of the Mess Hall and functions as the submarine's operational brain. Here Grimoire discovers Mortuga's final course corrections, a partially erased logbook, and the infamous six-socket switchboard that powers theatre stage hydraulics. Restoring control room functionality requires solving the switchboard plugs puzzle, after which several previously dark corridors illuminate on your UI minimap. Treat the Control Room as a gating puzzle hub: until the switchboard is correctly wired, you cannot retrieve the Illusion Theatre master key from the relay cabinet.

Adjacent instrument panels include the compass pinboard preview used in a later dedicated puzzle—photograph the initial needle positions in your notebook. The Control Room also contains a safety interlock tied to the Airlock Grotto; attempting to access exterior maintenance before completing switchboard wiring triggers a Spears quip but no soft-lock. Consult compass pinboard solutions once you recover the missing magnetic needles from Cargo Hold crates.

Key Puzzles During First Exploration

Beyond the switchboard, this phase typically includes the live Mess Hall dials, a card catalog in the Parlor referencing Jennifer, Margaret, and Patricia lens cards, and the corridor safe leading to Dream Chamber supplies. Always confirm completion with the keyhole icon in the upper-right corner; it validates solutions and unlocks tiered hints if you used trial and error. For a general overview of skipping optional challenges, see how to complete puzzles.

1. Clear the Parlor introductions and collect all question-mark dialogue topics.
2. Solve Mess Hall dials to access the galley storage cache.
3. Investigate the Child's Room for family clues and Dream Chamber foreshadowing.
4. Wire the Control Room switchboard to restore theatre power routing.
5. Retrieve the Illusion Theatre key and enter the locked crime scene.
6. Return to Stonetop Inn or town square if map hints flag missed hotspots.