Klaus Gremme, a retired instructor from the Baltic Sea's combat swimmers, travels to Lake Constance to see his son Thomas and grandchildren. He abandoned his wife and Thomas when he was a young boy, and they are unaware of his presence. Klaus stays with Mona, a single mother living across the street from Thomas. Their reunion is rocky, but Klaus persists in trying to connect with his son and family. However, he repeatedly clashes with Mona, who is a pacifist. Slowly, Mona's children, Linus and Claire (who has Down syndrome), begin to warm up to the solitary man. Ultimately, Klaus’s attempt to reconcile with his family appears unsuccessful, but he may have unexpectedly found a new family with Mona and her children.
