The film is based on the actual events of the Portland Spy Ring trial in the U.K. A disgruntled Navy Clerk is transferred to a secret research establishment and is subsequently black-mailed/paid by Czech intelligence to procure secrets for them. He seduces the secretary who controls the most secret documents, and they enjoy the fruits of their treachery until the British authorities begin to close in on them.
When his grandfather dies, George Westcott (Patrick Doonan) returns home from India to collect his inheritance -- only to find that the will has mysteriously gone missing. As his greedy relatives try to seize the estate, George gets the help of a movie star (Greta Gynt), a window cleaner (James Hayter and a police inspector (Herbert Ross) to track down the missing will. It seems that justice will prevail -- but is George Wescott really George Wescott?