The protagonist, an 11 years old boy, befriends a 10 years old girl while on vacation. The girl likes to swim in the nude, and isn't bothered by his presence. But later they are discovered by a group of local bullies, and they profoundly harass the girl and force her to come out of the water naked (while the boy doesn't muster up courage to stand up to them) which greatly traumatizes the girl. Now as a child, the reason for why this was so traumatic isn't very clear (she wasn't bothered by the boy protagonist, for example) but hey, who likes being ogled and a subject of nasty remarks while naked? But for an adult, it becomes clear that the girl panicked because she feared the the bullies (who were somewhat older then her - their leader is 15 and the others are 12-13) may actually molest her, and that's why she was so traumatized by (and ashamed of) the whole incident.