Although Grandpa Kalle is willing to teach his granddaughter Luise how to swim, this project is not crowned with particular success. The problem: Grandpa Kalle doesn't know how to swim! However, he does not want to admit this to himself, but especially not to others. But when Claire, hated neighbor who also happens to be the lifeguard at the same time, discovers this, she can’t let go of this fact and before she knows it, she teaches an entire pensioners club on how to swim.