As pro-fascist sentiment grows in Gdańsk, Jews begin fleeing the city en masse. Professor Zimermann, an expert in radio waves, also plans to leave, but the Nazis refuse to let him go. His case draws the attention of a mysterious agent named Sonia, who enlists Bednarski’s help. They learn that Zimermann is aboard the ship Stella, used by Fritz Herman to transport Jews from Gdańsk to Sweden. However, a criminal gang aboard the vessel robs passengers of their valuables and disposes of the victims. Bednarski joins the crew as a steward, while Sonia poses as a Jewish refugee. Once on board, they manage to contact Zimermann and save his life—along with the lives of other passengers.