A wayward young woman running from her past is reunited with her sister after they became separated during the war. While she worked on the streets, the sister established a professional career as a psychologist.

The girl Marianne inherited a motorboat called “Eintracht” from her parents and struggled to get her to drive it with her uncle. There is a row with the new engineer Michel the evening after the first trip. He leaves - out of jealousy. Instead of him, Marianne takes three funny musicians with her who are looking for work. The trip to Hamburg on the Elbe initially ends on a sandbank, from which another barge, the "Petrel", frees them. Michel has now been hired there. After a few complications and pointless fights, because Marianne has long been in love with Michel, there is the well-deserved happy ending.