The ship stoker Heini Holler leaves Greece for health reasons and reports to the consulate of fascist Germany. The consul sends him back to Hamburg. He had previously reported him to the Gestapo there as politically suspicious. On his arrival, Holler is immediately arrested. His comrades kidnap the consul and demand an exchange for Heini, which is to take place in Marseille. The Gestapo agree to this as a pretense and secure the support of the French police to arrest the kidnappers. However, the solidarity of the sailors in Marseille is stronger and Heini is able to cure his lung disease in the Soviet Union.