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⌾Servant of the Lake Walkthrough
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Puzzles

Pest Control — The Mouse in the Cellar Wall

The Servant of the Lake cellar mouse in three steps: magnet for the key, click the hole again to draw it out, then the sledgehammer when it runs back across.

Last updated 2026-08-18

Light spoilers. This page names rooms, items and characters you meet, but keeps the story beats out of it.

Three steps, and almost everyone stops after the first.

  1. Use the magnet on the hole to pull out the key.
  2. Click the hole again. This draws the mouse out.
  3. When it runs back across, hit it with the sledgehammer.

The key is what you came down here for, so step one feels like the end of the puzzle. It is not — the achievement is in steps two and three.

Pest Control in three steps: magnet for the key, click the hole again to draw the mouse out, sledgehammer on its return pass

Finding the hole

Take both tools with you: the hammer and the magnet. At the fork, go left — the mouse hole is on that side.

If you arrived without the hammer, you will get the key and nothing else, and the block will close behind you.

The achievement

Pest Control. The official clue is unhelpfully terse:

"The hole is inhabited. Use the sledgehammer!"

It tells you the tool and says nothing about having to make the mouse appear first, which is exactly why players collect the key and walk away thinking the hammer was for something else.

Timing the swing

The mouse does not sit still to be hit. It comes out, crosses, and comes back — swing on the return pass. Missing is not fatal; you can draw it out again.

If you already left with the key

Walking back out of the cellar is what ends it. Inspecting the Cellar fires, Day 2 closes, and Day 3 begins somewhere else entirely — the cellar you return to in the post-credits route is a different sequence with different interactions, and the hole is not part of it.

This one is lost two ways rather than one. Taking the key and leaving is the common way. The other is arriving without the sledgehammer at all, in which case there was never anything you could have done down there, and no prompt told you so.

Recovery is a save from before you entered the cellar, taken early enough that you can still pick up both tools.

Where this sits

Day 2 Night, in the cellar, during Inspecting the Cellar. It is the last interaction of Day 2.

Before this, on the balcony, Garbage Disposal wants you to throw everything over the edge — clue: "This is disgusting! Throw them down! The balcony isn't a trashcan!"

Full day on the Day 2 walkthrough. Next up is Day 3 and the alchemy.

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