The successful Hamburg veterinary pharmacist Dieter Walling half-heartedly retires from business life in order to keep his promise to his wife Ingrid to move with her to her home in Munich. Dieter is actually reluctant to make this move. This makes the request from the seal sanctuary in St. Peter-Ording to develop a serum all the more welcome, especially as a former close friend from university works at the sanctuary. Dieter decides to take care of this assignment personally. On site, Dieter not only meets Willi, with whom he still has an old debt to settle, but also Anna, the beautiful icon of their wild student days. The round dance from days gone by seems to begin again. But the situation escalates when Dieter confesses the dark secret of those days to Willi in the mudflats...