A corpse washes up on the North Sea beach. The dead man is Alexander (August Zirner), the husband of the beautiful, withdrawn Bettina Halbach (Ina Weisse). Although their marriage was unhappy and their relationship had been on ice for a long time, Bettina had always stood by Alexander during his severe kidney disease. Together they owned a summer house on the island, to which Bettina retreated for several months. In the end, she also lived out her relationship with her lover (Jürgen Vogel) there. The marriage of Tom and Ulrike (Nicolette Krebitz), who runs a guesthouse on the island, therefore goes through a deep crisis.
Everything speaks for a death without external influence. No one doubts; not even the young policewoman Maike (Bernadette Heerwagen), who has been connected to the family since childhood, at first. The fact that a tourist is unable to assess the pitfalls of the tides is no surprise to anyone here. But Alexander should have been familiar with the Wadden Sea after all his visits. Daughter Mia (Leonie Benesch) thinks a suicide is out of the question – Alexander would have said goodbye, at least to her. When Maike finds out that Alexander spoke to Tom on the phone shortly before his death, but Tom denies any involvement in the case, she wants to find out the last moment of truth.
Entrenched conflicts and failed communication also seem to strain the relationship between Bettina and her daughter Mia. Maike’s investigation is not helped by the personal relationships she maintains with the islanders. Alexander’s burial at sea finally brings the islanders together at the harbor. A silent showdown ensues; and Maike grasps the full tragedy of the estrangement of two people.