A secret jet aircraft capable of traveling three times the speed of sound is being developed by a group of scientists. On the day of the test flight, one of the scientists dies in a mysterious accident, and there are many arguments concerning the flight itself; some think it should be ground-controlled while Heathley (James Donald) wants it to be a manned flight with himself at the controls. Conflict also arises when one of his fellow scientists, taking advantage of Heathley's lack of attention toward his wife, Lydia (Phyllis Calvert), makes some moves on her. Then there is the question of just who is the enemy agent on the project.
James Donald
Phyllis Calvert
Noel Willman
Herbert Lom
Robert Beatty
Patric Doonan
Walter Fitzgerald
Muriel Pavlow
Maurice Denham
Marjorie Fielding
Herbert Lomas
Geoffrey Denton
Cyril Chamberlain
Hal Osmond
Caven Watson
Marianne Stone
Stanley Maxted
Hartley Power
Philip Ray
Johnnie Schofield
John Warren