Novelist John P. Marquand's soft-spoken Japanese detective Mr. Moto was brought to the screen in an entertaining 1930s B-picture series by 20th Century-Fox. But when the same studio purchased Marquand's novel Stopover Tokyo in 1957, Mr. Moto was totally excised from the screenplay. The film's main character is an American intelligence agent, played by Robert Wagner. Assigned to protect the US ambassador to Japan (Larry Keating) from assassination, Wagner is stymied by the ambassador's refusal to cooperate. This makes it all the easier for communist spy Edmond O'Brien to set a time bomb in the embassy. Wagner races against time to neutralize the bomb, and in so doing loses the love of Joan Collins, who wants no part of the espionage racket. Stopover Tokyo was a rare excursion into directing by Oscar-winning screenwriter Richard L. Breen.