After Ace Murray, a former airmail pilot who now performs stunts in Speed Hardy's carnival air show, makes an impromptu "double parachute" jump with his brother Bud, Speed offers Bud a job with his troupe. Against the advice of Ace, Bud, who is attracted to Speed's young wife Ann, quits college and joins Speed's troupe of "Black Cats." At Speed's request, Bud and Ann perform the double parachute jump together and become the show's main attraction. When the young couple blow off course during a jump, however, Speed rails against Bud in front of Ace. Furious at Speed's treatment of Bud and his callous attitudes about safety, Ace, who is also fearful of Bud's growing passion for Ann, prepares to leave the troupe with his brother. Ann, however, talks Ace and Bud out of quitting, but later agrees with Bud that he should leave before their romantic feelings for each other become known to the jealous Speed. Just before saying goodbye, Bud and Ann take a final ride together and run out of gas in mid-air. Because of a dense fog, Bud and Ann must crash land the plane and find overnight shelter in a deserted cabin. The next morning, Ann and Bud declare their love for each other, and Ann decides to ask Speed for a divorce. When Speed shows up at the cabin, he is strangely calm and understanding, and later, when Bud approaches him in his tent, he happily consents to divorce Ann and suggests that he and Bud perform a new stunt for the show. Eager to please Speed, Bud agrees to do the "head-on collision" trick, which requires that both pilots bail out seconds before their planes collide. Minutes before the collision is to take place, Ann and Ace learn from Screwy, the troupe's alcoholic pilot, that Speed has cut Bud's parachute with his knife. As Bud and Speed prepare for the collision, Ace races to stop Speed. Unable to out-maneuver Speed, Ace finally crashes into his plane, sacrificing his life to save his brother.