Drei Mann und eine Sommernacht.

Three men accidentally end up stranded on an island in the Baltic Sea: friends Achim and Klaus and railroad worker Erich Spalteholtz. Both friends try to swim ashore to get help. In the process, they have adventures with the police as well as with the enchanting girls Anne and Brigitte! However, before Erich Spalteholtz is rescued from the island, he helps himself alone - thinking that Achim and Klaus have drowned...