A girl called Zara loves going to her friend Mia's house. But Mia's older brother and his mates are often there, and they've started getting the younger girls to do things — daring them, showing them stuff they shouldn't see, pressuring them to keep up with the "big kids." Mia goes along with it because it's her brother, and because being included by the older kids feels exciting. Zara doesn't like a lot of it, but she doesn't want to seem babyish, and she doesn't want to stop being able to go to Mia's. So she goes along too, ignoring the uneasy feeling that some of it has crossed a line she can't quite name.