Click on the blue flyer on the left wall of the headless statue to receive the rodent control reward task.

Second, the task of rodent control strategy:

Location of the first mouse:

The first mouse runs back and forth in the restaurant.

Location of the second mouse:

We can see the second mouse in the corridor leaving the armory.

Location of the third mouse:

1. At the beginning of Chapter 10, we entered the room to the right of three statues.

When we enter the dark corridor of the right library, we can find the last mouse. This mouse can't be found in chapter 9, but we can find the last mouse from Lyon's perspective after entering chapter 10.