James Mason is the disgraced RN Commander ("Heritage") dragooned from the service after being tricked into sharing secrets with the Nazis. Bent on revenge, he determines to track them down. His journey starts at an old cottage where he mets Joyce Howard ("Laura") who has come to visit her uncle, but discovers a body instead - a body that has disappeared by the time the police arrive to investigate. Initially hostile and wary of each other, the pair must work together to get to the bottom of this most sophisticated of criminal enterprises that appears to revolve around the operations of the "Ch...