‘Gunnerside’ fail to locate their drop-point and the pilots insist on turning back. But Knut Haukelid claims to know where they are and they parachute out over the snow-covered mountains. Far from their drop point they start looking for the ‘Grouse’ team, and after strenuous days they finally join up. Werner Heisenberg is now back in favour with the military and is appointed director of the Keiser Wilhelm Institute in Berlin. He is promised unlimited support. ‘Gunnerside’ abandon the original plan to shoot their way across the bridge and into the heavy water factory. Instead they will try to climb the deep gorge under the bridge. It is considered impossible and therefore not protected by the Germans. They succeed in blowing up the factory and Claus Helberg stays behind to continue observing the factory. The Germans mount a major search for the saboteurs, and order an immediate rebuilding of the heavy water facilities!