The love that Judy, a young painter, feels for Alan, a promising doctor to whom she is engaged, falters when Bill, an old friend, suddenly appears.

Jewel thieves, murder, and a manhunt swirl around a sailor off a cargo ship in post-war London.

In England, an eccentric police inspector, an earnest test pilot and a spunky female reporter team up to solve the mystery of a series of test aircraft which have disappeared without a trace while over the ocean on their maiden flights; unaware, as they are, that a spy ring has been shooting the planes down with a ray machine hidden aboard a salvage vessel which is on hand to haul the downed aircraft aboard, crews and all.

In the London of 1537, two boys resembling each other exactly meet accidentally and exchange "roles" for a short while. After many adventures, the prince regains his rightful identity and graciously makes his "twin" a ward of the court.