Several murders of nuclear scientists, that baffles Scotland Yard, occur in London around the same time that Bill Locklin, a special officer from the United States State Department, arrives to oversee the transfer of Professor Leon Dushenko, a Russian scientist who has fled the USSR. An attempt on Dushenko's life is made with a monkey's paw-print found at the scene.

• Merton Park Studios
• Richard Conte
• Rona Anderson
• Russell Napier
• Sylva Langová
• Colin Gordon
• Donald Bisset
• John King-Kelly
• Bernard Rebel