A priceless ruby, belonging to a Far Eastern prince, is stolen from him whilst he is on a visit to England. The ruby was destined for the prince’s bride-to-be and a scandal must be avoided. Poirot is asked to attend a Christmas celebration in order to apprehend a jewel-thief.

A valuable emerald necklace has been stolen and Poirot is asked to help. At the scene of crime, Poirot finds two clues: a glove and a cigarette case engraved with initials. But for Poirot, two is too many.

A middle-aged woman, Mrs Pengelley, tells Poirot she thinks her husband is trying to poison her. Poirot believes her and travels to Polgar with in Cornwall but arrives just hours after she dies. Poirot blames himself for being late and vows to bring her killer to justice.

Hercule Poirot and Hastings are discussing investments and Poirot informs Hastings that his only speculative investment is in fourteen thousand shares in Burma Mines Ltd which were given to him as a gift for services rendered.

Poirot is not interested in investigating some of the cases which appear in the newspapers when Hastings tries to bring them to his attention. These include ones about a bank clerk, Mr. Davis, who disappears with fifty thousand pounds of securities, a suicidal man, and a missing typist. He is put on the spot though when visited by a Mrs. Todd who is determined that he investigate her missing cook. Challenged, he decides, with some humour and to avoid an argument, to take the seemingly trivial case. Eliza Dunn, a middle-aged woman, walked out of her job and the Todd's house in Clapham two days ago without working her notice. She has not communicated with her employer since, except for sending for her trunk that very day. What can Poirot make of this?

Elderly Mr Maltravers is found dead in a field, with his grieving wife claiming it has been natural causes. But as he recently took out life insurance, the company brings in Poirot to establish if it was suicide.

Self-made millionaire, Lord Charles Mayfield is throwing a house party, what better way to conceal the true nature of a meeting to discuss top-secret plans for a fighter plane, as well as catching out a spy in the process. But the plans are snatched and only Poirot can uncover the truth.

Poirot assists a young woman in proving to her deceased uncle that her education was valuable. They must solve the puzzle of his will or else she will be left with no inheritance.