Is a human even waterproof? Willi hadn't told anyone yet, but he had a terrible suspicion: Humans, Willi thought, are not waterproof at all. Or maybe just everyone else is, and he isn't. Willi, 8 years old, can already do quite a lot: sing loudly in the children's choir, scare girls with squeaky bike brakes, hunt for slugs, and go sledding on plastic bags. However, there is one thing he really doesn't like to do, and that is: swim. To be precise, Willi is even an enthusiastic non-swimmer. A coward, claims his brother Tobi. And indeed, Willi avoids water whenever he can. Even on vacation, he is the only one in the family who doesn't go into the sea. "I could, if I wanted to," says Willi. "You know that. But I don't want to." After all, there must be a reason why we don't have webbing between our toes.