John Wayne cast aside his usual Western gear to portray a tough Irish-American detective on assignment in London to catch a crook who fled the United States to avoid extradition. Wayne's partner in criminal hunting is a British Inspector (Richard Attenborough) with a very different personal style. After a rough bit, they become partners and cooperate in a rousing batch of car chases, false and good leads, booby traps, etc., before they trap their man. Detective Wayne finds time for some heavy flirting with constable Judy Geeson (TO SIR, WITH LOVE), who would prefer that Wayne's flirting was considerably less heavy. Screenplay co-written by Christopher Trumbo (son of Dalton Trumbo).