The U-949 is in danger during a test drive due to Commander Buchner's orders. Forster comes across a trail in a casino and makes the acquaintance of the German Bettina Gruber.
While Swinburne sets sail with a technologically upgraded ship, Ehrenberg makes a serious decision in Kiel. Forster tries to get a traitor out of the country.
After Wilhelm Hoffmann learned the truth about his son Klaus, he gets into a fight with Hannie. Ehrenberg has to say goodbye to Greta. In Portugal, Forster's plan gets out of hand.
Swinburne's destroyer sinks two submarines on the Atlantic, then he hunts U-949. Forster observes a secret meeting between consul Gruber and the American Gardiner.
U-949 meets a Japanese boat to take over heavy cargo - gold. Wilhelm Hoffmann receives an invitation to Lisbon. Forster tells Klaus Hoffmann under duress what he knows.
After a bomb explosion, Forster and Klaus Hoffmann hide with the Portuguese Ines, while Wilhelm Hoffmann arrives in Lisbon. U-949 is heading for their new destination.
Klaus Hoffmann pursues the German agent Weiss and discovers valuable information. U-949 is under heavy fire from Swinburne's destroyer - until Commander Buchner dares a maneuver.
The U-949 reaches Portugal and unloads the gold. When Ehrenberg returns to Kiel, he finds Greta with her husband again. Klaus Hoffmann and Forster reach their goal through blackmail.
