Although it takes Anne Frank a while to become friends with Peter Van Daan, one of the first things they bond over is Mouschi, the cat that Peter brings into the hideaway with him. Anne had been forced to leave her own cat at home. Dismissing Peter’s claim that Mouschi does not like strangers, she simply says that she will no longer be a stranger.

Peter’s parents tend to squabble, which at first surprises Anne, because her own parents do not argue and she sees the other adults’ behavior as childish. One thing that Mr. and Mrs. Van Daan argue about is money. She resents him smoking, because it is expensive. Mr. Van Daan also criticizes his son for being insufficiently studious. Peter often plays with his cat when he is supposed to be studying.

At Hanukkah, Anne surprises the others by giving every person a gift, most of which she made herself. She has even made a toy for Mouschi. Peter goes to his room, and when he comes back pretending to have the cat hidden in his coat, his father gets annoyed. It is actually a wadded up towel, but the joke just irritates Mr. Van Daan more. He announces,

We’re getting rid of it …. I’m sick of seeing that cat eat all our food.

Peter contradicts him, saying he only feeds him scraps, and Anne loudly objects.

Mr. Van Daan, you can’t do that. That’s Peter’s cat! Peter loves that cat.

Peter then announces, “If he goes, I go.”