American bomber pilot Captain Jeff Dakin is shot down on a bombing raid over German-held territory. As his crew bails out, Jeff sees his bombardier brother, Lt. Danny Dakin, machine-gunned to death as he is drifting to earth. After being taken prisoner Jeff learns the name of the man who murdered his brother---Nazi ace Major Von Streicher. In the concentration camp he begins a plan of escape with two other prisoners; Czech prisoner Captain Paul Husnik and a young Russian doctor, Alexandra "Alec" Zoreisch. The three escape during an air raid. Jeff begins to take a dislike to Paul over several incidents that arouse his suspicions. Actually Paul is Gestapo officer Paul van Brock who has engineered the escape in the hope that the Alec will lead him to the leaders of the underground movement. They manage to reach the home of a friend of Alec's father, where Paul reveals his true colors by killing the underground leader and calling the Gestapo.