

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.

Richard Conte
Bill Locklin

Rona Anderson
Julia Jackson

Russell Napier
Supt. John Harrington
Sylva Langová
Hilde Heller, chief spy

Colin Gordon
Harry Martin - reporter

Donald Bisset
Editor Harris
John King-Kelly
Spy Henchman
Bernard Rebel
Vinson - Spy Henchman

Arnold Marlé
Prof. Leon Dushenko

John Horsley
Det. Sgt. Gibson