While preparing for a top priority mission, Gen. Savage replaces a sick crewman with a hotshot gunner, only to discover too late that the man has a bad reputation as well as a negative attitude. Joe Waller is a washed-out pilot trainee who takes out his resentment on his fellow crew members. The resulting friction threatens the integrity of the crew, even before Waller is forced to replace the fatally wounded bombardier, making him the most important man in the entire mission.