After breaking up with her unfaithful boyfriend, Katharina Reiff urgently needs a change of scenery. Together with her 16-year-old daughter Nele, she travels to her mother Marianne, who lives on a small island in the North Sea. On the way there, Katharina observes a man being followed by two dubious figures. Good-natured as she is, she takes Sebastian, the stranger's name, with her to the island. When Sebastian's shady pursuers turn up a little later, the shrewd islanders join forces to shed light on the matter.