what is the mouse doing

A: I'm in a big trouble!

B: Why is that?

A: I saw a mouse in my house!

B: Oh, well, all you need to do is use a trap.

A: I don't have one.

B: Well then, buy one.

A: Can't afford one.

B: I can give you mine if you want.

A: That sounds good.

B: All you need to do is just use some cheese in order to make the mouse come to the trap.

A: I don't have any cheese.

B: Okay then, take a piece of bread and put a bit of oil in it and put it in the trap.

A: I don't have oil.

B: Well, then put only a small piece of bread.

A: I don't have bread.

B: Then what is the mouse doing at your house?!