Franz visits the Swedish Mariner's House, where he learns that his father is a Pole named Kurkowski. Pastor Eriksson gives him a letter in which the father asks that his son be able to behave decently during the difficult time of war. Armed thieves attack Franza Street, but one of them, Staszek, turns out to be his former friend. Franz visits his mother and wants to find out more about his real father, but she avoids the conversation. But then she meets her son and admits that she once loved Kurkowski, but she thought he died at sea. Then she became involved with Lothar, who took care of her and her little son Franz. He does not reveal to his son the real motivation behind the relationship with the German.

Kurkowski is taken to a German research center on the Baltic Sea. Engel tries to force him to cooperate voluntarily. Kurkowski refuses. At the Kriegsmarine headquarters, Franz meets Greta. Greta does not hide the fact that she would like to meet Franz during the Gauleiter Cup regatta that will take place the next day.