During the Napoleanic Wars, members of the Prussian Lützow Free Corps steal a French war chest from the house of collaborator Kerstinn, but their captain Friesen is captured and sentenced to death. But Friesen is saved by French Sergeant Fleuron and they flee the occupied city together. Kerstinn's daughter Marie is disgusted by her father's disloyalty and has also fallen in love with Friesen. When she learns about a trap that is being set for Lützow Free Corps, she sets out to warn them with the help of her father's clerk Püttchen, a Lützow sympathizer.

Based on the novel of the same name by Harry Turk. 1944. In occupied Poland, a railway line is being built to transport lead ore to Germany. The Valley of Seven Moons is restless, with construction materials disappearing and people vanishing. The occupiers feel uneasy on foreign soil. Despite increased security, partisans carry out one act of sabotage after another, hindering construction in every way possible. The German Rudek and the Jewish girl Martina, who at first stand aside from any struggle, join the partisan detachment.