MOUSE: P.I. For Hire: Glugging From The Deep Walkthrough

Late in MOUSE: P.I. For Hire, “Glugging From The Deep” stops feeling like a standard campaign chapter and starts acting like a final exam for everything the game has taught so far. It uses hub NPCs, side quests, traversal puzzles, underwater gating, and then caps the whole thing with a timed submarine boss encounter against Ze Professor. The cleanest way through is to divide the mission into three jobs: finish the diving suit setup first, sweep the dock area for major secrets before boarding, and treat the boss as an objective sequence rather than a straight damage race.

That approach matters because this level is very good at wasting your time if you improvise. Players usually lose minutes in one of three places: trying to enter underwater routes before all three suit pieces are assembled, boarding the submarine before grabbing nearby collectibles, or shooting the wrong targets during the boss fight. If you want a reliable clear on PC or console, keep your route disciplined and let the mission’s logic drive your order.

Understand the gate before you start exploring

The core trick in “Glugging From The Deep” is that underwater progress is hard-gated by a full gear set. You need the rubber suit, the heavy spiked boots, and the diving helmet before the level fully opens. The game frames this like detective work and side-content cleanup, but it is really mandatory progression. If you are searching the docks and wondering why a path feels incomplete, assume you are missing one of those pieces before assuming you missed a jump or hidden switch.

• Rubber suit
• Heavy spiked boots
• Diving helmet
• Optional but recommended: dockside collectible sweep before boarding the submarine

The big progression warning: talk to the NPCs when the mission points you back toward town or the waterfront. Tammy is the important information hub for this chapter, and Eddy is specifically tied to the heavy spiked boots. This is one of those MOUSE levels where dialogue is not flavor; it is the routing layer. If your objective feels vague, revisit Tammy first and make sure every lead has been exhausted before you roam.

The efficient order for the diving suit setup

Once the chapter shifts into the hunt for underwater gear, do not scatter your attention across every side alley. Follow the main leads until the suit assembly is almost done, because that cuts down on backtracking later. A practical order is: advance the main objective until Tammy points you toward the needed gear chain, pick up the boots from Eddy when that step opens, then finish the remaining helmet and suit leads in the same general sweep before returning to the dock objective. The exact micro-route can feel a little different depending on how thoroughly you explored earlier, but the priority does not change.

This is also the point where finding Steve matters, because the chapter’s story handoff pushes you from investigation into submarine assault prep. If you are trying to play this like a pure shooter mission, the pacing can feel odd. It helps to think of the first half as pre-raid logistics. You are not being delayed from the “real” action; assembling the diving gear is the mission structure.

If the objective marker seems stuck, the most common cause is not combat or a missed pickup. It is usually an unspent conversation step. Re-check Tammy, re-check Eddy, and make sure you actually received the relevant item or update before heading back to the water routes. This chapter hides its progression behind detective-story flow more than behind mechanical difficulty.

Do your dockside cleanup before you board the submarine

Once the diving suit is complete and the path toward Ze Professor’s submarine is open, resist the urge to board immediately. This is the best window for cleanup if you care about collectibles or a smoother return route. Multiple achievement-related items are spread around this mission, and the easiest way to keep them straight is to think in zones rather than in item types.

• Vents
• Rooftops
• Shipping containers
• Crane and dock machinery areas
• The submarine approach area itself

That zone-based sweep matters because different walkthrough descriptions of some collectibles vary slightly in wording, even when they agree on the broad area. So if you are missing a baseball card, comic, newspaper, or schematic, do not assume the game bugged out. Re-sweep the named zone carefully, especially vents and container tops, which are the easiest places to “technically see” without actually collecting.

The dock machinery puzzle is worth special attention. This chapter includes north/south switch interactions that manipulate crane movement and can reveal a grappling point leading to a secret route. If you see compass-marked switches around the crane section, hit both relevant switches before moving on. Players focused only on the story clear often skip this because it looks like optional scenery logic, but it is tied to one of the mission’s more easily missed secret paths.

You should also watch for destructible walls marked with an X. At least one warp pipe shortcut is hidden behind that kind of breakable surface, and opening it up can save time during cleanup or return movement. If you have the right explosive or launcher tool available and a wall looks suspicious, test it. MOUSE uses environmental shorthand consistently enough here that the marking is a genuine hint, not decoration.

Near the submarine encounter area, there is also a schematic tied to a safe that you reach by climbing a nearby ladder and using the tailpicking mechanic. Grab that before you trigger the boss sequence if you are doing a completionist run. It is much easier to handle in a calm pre-fight pass than during post-battle tunnel vision.

How to handle Ze Professor’s submarine boss fight

The submarine battle is where most failed runs happen, and the reason is simple: the fight looks like a boss duel, but it is really an objective puzzle under pressure. Your target priority matters more than raw aim. If you spend too long firing at the wrong part of the encounter, the timer will punish you even if your movement is clean.

Phase 1: destroy every turret first

Start by wiping out all visible turrets on the submarine. Do not split attention between turrets and tanks, and do not tunnel on Ze Professor. The turrets are the key that disables the protective shields around the tanks. As long as even one turret is still active, you are not really progressing the fight. This is the most important rule in the entire encounter.

Use your most reliable accurate weapon for this part. The goal is fast target acquisition and clean destruction from safe movement lines, not flashy burst damage. The common mistake is leaving one awkward turret alive on a far angle, then wondering why the next step is not opening. If the shields are still up, stop shooting everything else and scan the arena again.

Phase 2: burn the tanks once the shields drop

When the shields are disabled, switch immediately to the tanks. This is the strict timer section, so hesitation hurts more than imperfect aim. If you have a heavier damage option, this is the moment to use it. You are no longer solving the encounter; you are racing the mission clock. Keep moving, but keep your route compact. Wide panic loops waste seconds and usually break line of sight on your real targets.

Do not get baited into cleanup behavior here. This is not the time to search for pickups, admire the arena, or chase Ze Professor around. The tanks are the check. The timer is telling you exactly what the mission cares about, and the fastest clears come from obeying that priority without improvising.

Phase 3: finish Ze Professor, then leave without skipping the last secret

Once the objective hardware is gone, the rest of the encounter opens up and Ze Professor becomes the proper finish. By that stage the hardest part should be over if you handled the order correctly. The level’s real demand is sequencing, not a hidden final combat gimmick. Stay composed, finish the fight, and be ready for the exit sequence.

There is one more easy completionist trap after the boss: do not rush straight to the exit. A schematic is placed near the defeated angler fish boss at the level’s way out. Many players miss it because the emotional pacing says “leave now,” while the level design still has one final reward tucked beside the post-battle route. Take a final look around before you commit to the transition.

Side quests and post-mission turn-ins

“Glugging From The Deep” also ties optional content back into collectible completion. If you picked up side-quest progress earlier, remember to return to the P.I. hub and related NPCs after the mission. One notable example is the Bozo-related side quest, which feeds into a baseball card reward on return. That makes this chapter slightly deceptive for completionists: a full clear is not just what you grab inside the submarine route, but also what you turn in after escaping it.

That is why the best mental model for this walkthrough is not “beat the submarine boss and you are done.” It is “finish the dock chapter, clear the submarine chapter, then close the loop in town.” If your collectible totals look one step short after the credits of this mission beat, check your turn-ins before assuming you missed something in the combat space.

If you are stuck, check these failure points first

• You cannot progress underwater: one piece of the diving suit set is still missing, or an NPC conversation step did not complete.
• The tank shields will not drop: at least one turret is still alive somewhere on the submarine.
• You are missing a collectible: re-sweep vents, rooftops, containers, crane switches, the safe by the submarine area, and the post-boss exit path.
• Your 100% run still looks incomplete: return to town and finish any side-quest turn-ins tied to rewards.