Kersten, a professional killer, is brought in from the Continent by a jealous husband, Donald Edwards, to kill his wife Helene.
Two men visit the apartment of Emil Louba, a rich gambler, on the night of his death - each with a strong motive for murder!
In return for clearing his once shady record, Mike Stafford agrees to help Scotland Yard smash a big blackmail racket that has already caused three brutal deaths.
The crook Charles Valentine is aware that he is being followed by agent Number Six, but Six's identity is a closely guarded secret within Scotland Yard.
When Jack Burgess, a small-time estate agent, gets persistent calls from a mysterious Mrs Jackson to buy an expensive property, he decides to learn more about the deal.
Kidnapping an old lady, a gang of thieves take from her the key of a jewellery shop. While two of them rob the shop's safe, what starts as a £20,000 jewellery theft soon turns to murder!
A police officer in the dock awaits a life-changing verdict and reflects on the situation that brought him to be arrested.