Country squire Marcus Waverly calls on Poirot for help in dealing with kidnap threats against his son. Hastings is appalled by the thought of someone going around kidnapping children and it becomes a race against time to find the identity of the mystery letter writer.

Lovely young actress Valerie St Clair, engaged to marry Prince Paul of Maurania, is the only witness to the murder of Henry Reedburn, a shady and overbearing producer. Prince Paul appeals to Poirot to save Valerie from police suspicion, and the great detective finds he has a conundrum to ponder on, 'When is a murder not a murder?'

Lord Mayfield, an aircraft manufacturer, tries to trap a spy at his country house, but his plan goes terribly wrong. Lady Mayfield sends for Poirot, who tells a few home truths.

At a London restaurant where he often eats, Poirot notices that another regular customer has diverted from his usual meal. As old Anthony Gascoigne lies dying in Brighton, his estranged twin brother, Henry, falls to his death. A tragic accident, or murder? Poirot begins to see connections and decides the answer to the mystery lies in a blackberry pie.

Marie Marvelle, a Belgian film star, receives threatening letters from a chinaman which demand her famous diamond, the Western Star. Marie visits her old friend Hercule Poirot in London, seeking his help, and Poirot tackles the case with relish.

With the world on the brink of WWII, there is more political turmoil when it appears that the famous Peace Party is in fact a cover for the Big Four.

Poirot and Hastings are on board a ship steaming towards Alexandria. Poirot recovers from his usual sea-sickness to take an interest in some fellow passengers, especially the Clappertons. On arrival at Alexandria, Mrs Clapperton is found murdered in her cabin.

Hastings and Poirot are playing Monopoly when they are interrupted by Lord Pearson, the elegant Chairman of the London and Shanghai Bank. The banker asks them to investigate the disappearance of a Mr Ling - a highly-valued customer who before he went missing had arranged to sell Lord Pearson a map showing the location of a long-lost silver mine. Ling is found murdered, a young stockbroker is implicated, and Poirot has to untangle a complicated plot.

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.

A wealthy industrialist is found dead in his study. Is his death related to a discovery made at his chemical factory? And is his wife all she seems?

Living quietly in the small village of King's Abbot, sleuth Hercule Poirot becomes involved in the murder of successful industrialist Roger Ackroyd. The number of potential killers is almost as great as the population of the village itself. As Poirot investigates he sees that there might be a connection to the suicide of a local woman, and the death the previous year of her husband.

Within hours of the Bonfire Night fireworks beginning Poirot finds himself investigating a violent death in Hastings' mews garage.

Poirot is on holiday at the Palace Hotel, Rhodes, when an Englishwoman, Mrs Valentine Chantry, is poisoned. Poirot unravels several complicated relationships between those staying at the Palace Hotel.

Poirot calls to see the veiled lady of the title (Lady Millicent Castle-Vaughn) at her London hotel. Lady Millicent is about to be married, but a mean blackmailer called Lavington has got hold of a love letter she wrote years before to another man. Lavington wants twenty thousand pounds, and Poirot makes up his mind to recover the letter himself, even if it means impersonating a Swiss locksmith.

A glamorous nightclub singer turned spy has stolen the US Navy's plans for a new submarine, and an FBI agent called Burt is in London to catch her. Burt dismisses Poirot as a gumshoe, and Poirot is likewise not impressed by the self-important G-man. Poirot is drawn into the case when it appears that the submarine plans will fall into the hands of the Fascist government in Italy unless they are recovered. When Poirot meets a young couple who've got an amazing bargain on a prime apartment, he sees a connection with the spy case.

Poirot is called in when the British Prime Minister and his secretary are kidnapped in France on their way to a League of Nations conference - and he is given just a day and a half to solve the case.

An Australian shipping tycoon wants Poirot to check out his daughter's suitors. Then the young lady takes a trip on the Plymouth Express, and Poirot finds himself investigating a jewel theft on the train.

Poirot is drawn into the underworld of London's Little Italy when Captain Hastings looks for a new car, but instead finds murder.

While accompanying his friend Hastings to a dig in Iraq, Hercule Poirot becomes involved in the murder of an archaeologist's wife.

Hercule Poirot finds himself trying to solve the mystery of the Cloade family

A Mrs Ernestine Todd, from Clapham, asks Poirot to help her find her cook, Eliza, who has disappeared. Poirot, who aims to accept only really significant cases, is at first insulted by such a trivial request. However, after he sees the contents of the missing cook's trunk, he decides the case could prove to be worthy of his talents.

Poirot travels to Cornwall, summoned by a Mrs Pengelley, who suspects her dentist husband is poisoning her because he's fallen in love with his young assistant. Unhappily, Poirot finds Mrs Pengelley dead on his arrival, so he sets out to catch her killer.

Poirot tells a surprised Hastings he's decided to retire and suggests they take a holiday in the Lake District. On the way, Hastings befriends a young woman who is missing a collection of valuable miniatures. The case involves a famous writer and a beautiful woman in a sports car, and to the relief of Hastings Poirot's thoughts of retirement soon seem far away.

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.

Poirot attends the Victory Ball, a costume party where you are expected to dress as someone famous, as himself. However, when two members of a party of six dressed as characters from classical Italian comedy are subsequently found dead, Poirot finds himself working with Chief Inspector Japp to solve the case. The solution to the deaths of Viscount Cronshaw and Coco Courtney is to be found in determining the correct time of death and identifying an impostor at the ball. Poirot takes to the airwaves and reveals the identity of the killer on a live BBC radio broadcast.