U.S. Embassy employee Lee Cochrane and his wife, Sue, receive a shock when they discover that their 18-month-old son, Simon, has disappeared in London. He was last seen with their nanny, and the couple seemingly have no leads that might help police Detective Craig in his investigation. The media sensationalizes the incident, causing an unnecessary distraction as the couple prepares to confront the culprit face-to-face.
Set in 1931, the film takes place aboard a merchant ship, briefly harboured in South America. A young woman (Diane Cilento) boards the ship as a passenger, resulting in disharmony among the superstitious crew members. Virtuous seaman Anthony Steel protects the girl from the lecherous advances of captain Peter Finch.
British diamond smugglers use the radiowoman (Phyllis Kirk) from a freighter docked on the Thames to unwittingly "mule" their swag, hidden in cigarettes, past customs, not knowing that she has befriended an Inspector for the Thames River Patrol.
After being framed for a murder he didn't commit, Tom Penney (Donald Houston) serves his time and returns to his rural English home to establish a quiet life. When another victim is found, however, Tom is blamed for the crime and flees rather than returnng to prison. Hoping to find the real killer -- or killers -- Tom investigates while keeping a low profile to elude his pursuers, and a vital clue leads him on the path to possible redemption.
Long after being deserted by her husband, Linda Harrison will soon be free to marry her lover, Michael Carteret. But when her husband suddenly reappears, he attempts to blackmail the couple with a threat of ruining Michael's career. When her husband is murdered, Michael appears to be the only obvious suspect - but will the circumstantial evidence be enough to sentence him to death?
A killer called 'The Dark Man' commits double murder. This is witnessed by the young aspiring actress Molly Lester. The Dark Man tries everything to put Molly out of the way. Detective Inspector Viner of Scotland Yard investigates the murders.