The events of the fourth season of “Das Boot” begin in the summer of 1943: Klaus Hoffmann is celebrated as a hero in Berlin, but at the same time he is shadowed. His sister Hannie, whose marriage only exists on paper, has found a new job. Meanwhile, the navy suffers heavy losses in the Mediterranean. The film was directed by Dennis Gansel (“The Wave”) and the main actors in the six new episodes include Rick Okon and Rosalie Thomass.