The worn-out U-boat crew looks forward to returning home to La Rochelle in time for Christmas, but the ship is ordered to La Spezia, Italy, which means passing through the Strait of Gibraltar—an area heavily defended by the Royal Navy. The U-boat makes a secret night rendezvous at the harbour of Vigo, in neutral although Axis-friendly Spain, with the SS "Weser", an interned German merchant ship that clandestinely provides U-boats with fuel, torpedoes, and other supplies. The filthy officers seem out of place at the opulent dinner prepared for them, but are warmly greeted by enthusiastic officers eager to hear their exploits. The captain learns from an envoy of the German consulate that his request for Werner and the Chief Engineer to be sent back to Germany has been denied.