If it was murder, who was responsible? The dead man's wife, Julie? The young cafe assistant, Clive? Sergeant Cork, one of the pioneers of the newly formed C.I.D., applies his unique methods of detection to the case.

Lucy Beasley is certain that a crime is being committed in the Beasley household and she implores Cork to investigate. Is she a bitter, frustrated woman out to cause trouble, or are her fears justified?

When Cork and Marriott begin their investigations to find two criminals wanted for murdering a bank messenger; a tip off takes them to the London waterfront, where they uncover a sordid riverside trade.....

Cork and Marriott are called in to investigate the murder of a retired general's young wife, found strangled in a derelict bungalow in the grounds of an old country house is Devonshire.

Kate Seymour, a young star of the music hall, receives poison pen letters threatening her engagement to John Stratton, a stagedoor Johnnie.

Cork and Marriott are called in to investigate what appears to be a case of suicide when Mr Bertram, a respectable and deeply religious man, is found dead by his housekeeper, Mrs Holland.

An urchin sees a mysterious gentleman visiting Trumble, an ex-criminal, in his slum house. When Trumble is later found dead, the urchin goes to Cork.

Prince Frederick of Silecia arrives in London on a trade mission for his country. Cork is made responsible for his safety, and faces the problem of discovering those who are plotting the Prince's assassination.

In spite of opposition from the Melrose family, Cork is determined to discover the murderer of a laundry maid, whose body is found in their stable by a drunken coachman.

A strike at a factory; the army is called in to keep order, and during a riot outside the gates a striker is shot. Accident or murder?

Cook is summoned when an up-and-coming politician is murdered. His wife and the maidservant found a burglar standing over his body, but they are unable to distinguish any of his features.

Ella Barnes - a sewing girl from the East End of London - is found drowned in a canal. At the inquest, however, it is revealed that she had been attacked before she drowned.

Klein, a money lender, suspects fraud when a man called Carylon offers to sell him gold bars at a cut price. He calls in Cork and Marriott, who set a trap to discover whether Klein's suspicions are justified.