Sometimes, when they’re starting to run low on money, Jean Valjean will disappear for a while without saying where he’s going.
One night, Valjean is on one of these trips and Toussaint is sleeping, and Cosette hears someone walking in the garden. She looks out the window and doesn’t see anyone, so she decides she must’ve imagined it and goes to bed.
The next evening, she is walking in the garden, and she hears the noise again. She tries to brush it off, but then she sees a shadow wearing a round hat. When she turns around, whatever had caused the shadow is gone.
“The disquieting point about it was, that the shadow had assuredly not been a phantom. Phantoms do not wear round hats.”
When Valjean returns, Cosette tells him what she saw and heard. He spends the next few nights patrolling the garden with a club. A few nights later, he calls her out into the garden to show her a shadow caused by the neighbor’s chimney that resembles a man wearing a round hat.