What's going on with Dennis? Every time after swimming in the lake, he hides in the tent. When Jakob and Julius play a prank on him, they notice that Dennis is circumcised and feels ashamed because of it. And just at that moment, two girls, Sarah and Laura, show up in the tent. However, they don't find it funny at all, which many adults, including doctors, educators, teachers, and parents, often dismiss as a "small harmless operation." Through their older brother Frank, who happens to be the camp counselor for the boys, the five friends learn many new, interesting, and sometimes sad things about circumcision and phimosis, a condition that often isn't a condition at all. Almost incidentally, the teenagers get answers to some very intimate questions that boys have, answers that are rarely found in a biology book. It's all about the exciting physical changes happening to them.