The London and Scottish Bank is sending a huge shipment of Liberty Bonds to New York on the liner Queen Mary. Poirot, who suffers terribly from sea-sickness, is asked to see the bonds safely across the Atlantic.

Japp (who is really worried that failure could cost him his job) seeks Poirot's help in investigating a series of jewel thefts, and two remarkable things happen. Poirot falls in love (with the beautiful and clever Countess Vera Rossakoff) and he also meets a criminal intellect which he finds worthy of him. As the countess is his main suspect, Poirot spends most of his time with her - which for once leaves Hastings and Miss Lemon to do most of the actual detective work.

In the end, this case may have to be put down as the one that got away.

Poirot is called in to help a woman who lives in fear of her husband, and he is invited to a dinner party which goes horribly wrong.

Poirot prepares to spend a quiet Christmas on his own with a box of chocolates, but he has to give up his plans when the British government asks for his urgent help. Prince Farouk, a young member of the Egyptian royal family visiting London, has lost a famous ruby, and this is deemed to be a matter of national security.

Friends and family gather at a dinner party to mark the second anniversary of a woman's death. Meanwhile, Poirot is caught up in a coup d'etat and arrested as a spy, which prevents him from solving a murder at a French restaurant owned by an Italian in Buenos Aires.

When Poirot investigates the mysterious death of a despised art dealer, he finds that he has more than enough suspects from whom to choose.

Mrs. Opalsen's famous pearls are stolen and Poirot is happily on hand to investigate. A complex theft calls for a sophisticated solution. Unfortunately, Poirot is hindered everywhere he goes by being mistaken for 'Lucky Len'.

A string of thefts at a student hostel run by Miss Lemon's sister ends in death and Poirot has a number of plots and sub-plots to untangle. A certain mouse is the only witness to a string of murders.

Poirot and Hastings are on holiday in Deauville and receive a visit from Paul Renauld, who believes he's being cheated by Chileans. Renauld is kidnapped and his body is later found buried in a new golf bunker. French detective Giraud unwisely challenges Poirot to catch the killer before he can.

Lady Edgware has a dilemma in that her husband has consistently refused to give her a divorce. She asks Hercule Poirot to visit the man and see if there is any possibility of convincing him. When Lord Edgware is found dead, there is no great surprise, but there are a good number of suspects.

After collapsing with heart problems, Hercule Poirot visits a seaside health farm on Burgh Island. While there, the flirtatious heiress Arlena Stewart is found strangled on a secluded beach.