Franz, investigating the murder of a janitor, discovers that the killer fired a Russian rifle, suggesting the involvement of a Soviet spy. His investigation leads him to Redliński, who reveals that his daughter Hedwig may know the location of the scientific documentation.

Franz rescues Jadzia from Eva's hands and hides her with Redliński. Wulf follows them, trying to find secret documents. A group of spies goes to Pszczółki, where Jadzia's mother hid a suitcase with plans. The Germans organize an ambush, but Franz and Johann save Redliński and the girl.