After bailing out over Berlin, an 8th Air Force navigator is so successful in evading capture that he is selected for a very special mission by an underground group. The enemy has developed a toxic biological weapon they intend to use if the allies penetrate German territory. It is very important to get a sample of the toxin to the allies to test it and make a preemptive air strike to destroy the distribution point and a follow-up raid on the factory in Berlin. As allied forces near the German border, time becomes crucial. Instead of allowing their chosen man to continue the slow evading process, he is intentionally captured. Feeling betrayed, the navigator later realizes the urgency of the matter as the underground arranges a dangerous flight to an American airfield. A preemptive strike is flown, then the navigator must again fly through the flak-filled skies of Berlin...