London, 1929. Frank Webber, a very busy Scotland Yard detective, seems to be more interested in his work than in Alice White, his girlfriend. Feeling herself ignored, Alice agrees to go out with an elegant and well-mannered artist who invites her to visit his fancy apartment.

A chance discovery leads American mining engineer Ben Harris and acquaintance Harold to discover a lost city under the sea while searching for their kidnapped friend Jill. Held captive in the underwater city by the tyrannical Captain (Vincent Price), and his crew of former smugglers, the three plot to escape...

While vacationing in St. Moritz, a British couple receive a clue to an imminent assassination attempt, only to learn that their daughter has been kidnapped to keep them quiet.

Richard Hanney has a rude awakening when a glamorous female spy falls into his bed - with a knife in her back. Having a bit of trouble explaining it all to Scotland Yard, he heads for the hills of Scotland to try to clear his name by locating the spy ring known as The 39 Steps.

A couple vacationing in Morocco with their young son accidentally stumble upon an assassination plot. When the child is kidnapped to ensure their silence, they have to take matters into their own hands to save him.