American flying ace Jimmy Grant is a daredevil when it comes to flying airplanes, but when his friend, Royal Air Force Squadron Leader Charles Wyatt, encourages him to join the International Squadron of the RAF, Jimmy turns him down flat, saying that he intends to stay safe at home. Faced with a breach-of-promise suit, however, Jimmy agrees to deliver a new American-designed airplane to the RAF and leaves for Europe with his mechanic, "Omaha" McGrath. Over the airport, a heavy fog rolls in, and Charlie advises Jimmy to bail out of his plane, but Jimmy manages to land safely. The pilots who make up the squadron come from everywhere in Europe that the Nazis have invaded. The international crew even includes Americans such as Jimmy's friend, Lt. Rog Wilkins. Jimmy tries to interest his two friends in a night on the town, but both Charlie and Rog are now happily married and have no interest in chasing women. Left to his own devices, Jimmy pursues Jeanette, the young French woman who is assigned as his driver. While they are having dinner, the city is bombed by the Germans. Impressed by British courage and pluck and moved by the death of a child, Jimmy joins the RAF. Military discipline does not completely curb Jimmy's independent streak. During an air patrol, Jimmy's grandstanding results in the downing of a German bomber, but also causes the death of an RAF flyer. Only Charlie's intervention saves Jimmy from dismissal. Jimmy fails to take this lesson to heart, however, and when a dinner with Jeanette interferes with his patrol duty, he asks Rog to substitute for him. Even though Rog is exhausted by twenty uninterrupted hours of duty, he agrees and is shot down. After Rog dies, Jimmy wants to quit, but Charlie convinces him that it is his duty to continue Rog's job. Later Michele Edmé, Jeanette's boyfriend, draws the lot for a difficult mission. Jimmy, who believes he should be the one to risk his life, knocks Michele unconscious and takes the flight. Jimmy successfully completes the bombing mission, but is attacked by German planes before he can return home. After shooting down several planes, Jimmy is himself shot down and crashes to his death. At the airbase the squadron drinks a toast in tribute to him.