Theodore Honey (James Stewart), an eccentric "boffin" with the Royal Aircraft Establishment, is working on solving a difficult aviation crash problem. A widower with a 12-year-old daughter, Elspeth (Janette Scott), Honey is sent from Farnborough Airfield to investigate the crash of a Rutland Reindeer airliner in Newfoundland and Labrador, Canada. He theorizes the accident happened because of the tailplane's structural failure, caused by sudden metal fatigue after 1440 flight hours. To test the theory in his laboratory, a rear airframe is being vibrated at a very high rate in daily eight-hour cycles.