A Nazi spy ring is after a chemical formula that increases the power of ordinary gasoline for U.S. Army aviation use. Two U.S. chemical companies are developing the formula, with each working on half for security purposes. The spies get half the formula and know that either of two chemists, Robert Norton or Tom Fielding, knows the rest. They capture Fielding, through a ruse by gang member Linda Pavlo, and threaten the life of his sister Nancy and his mother if he does not give them the formula. To protect his friend Fielding, who does know the formula and is engaged to Nancy, Tom pretends to know the secret and boards the Dawn Express plane with the spy leader and his gang.
Michael Whalen
as Robert Norton
Anne Nagel
as Nancy Fielding
William Bakewell
as Tom Fielding
Constance Worth
as Linda Pavlo
Hans Heinrich von Twardowski
as Capt. Gemmler
Jack Mulhall
as Chief Agent James Curtis
George Pembroke
as Prof. Karl Schmidt
Kenneth Harlan
as Agent Brown
Robert Frazer
as John Oliver
Hans von Morhart
as Heinrich
Michael Vallon
as Argus
Willy Castello
as Otto
