Recovering from the horrors of World War I, British Army officer Arthur Hastings hopes to find peace and quiet at a country manor in the English countryside. But when the matriarch dies during the night from strychnine poisoning, Hastings enlists the help of an old friend staying nearby with other war refugees to help solve the murder: former Belgian police detective Hercule Poirot.

An ailing Poirot returns to Styles with Hastings nearly three decades after solving their first mystery together there in order to prevent an unscrupulous and ingenious serial killer from claiming more victims.

Poirot visits a garden fete, where a wasps' nest adds to the tension. He meets the son of an old friend who has his girl-friend, a fashion model, with him, and Poirot soon suspects that they are both in danger. He has to solve a mystery which includes cyanide, failing brakes and mixed-up love lives. Meanwhile, Hastings has a new hobby which Poirot finds helpful in cracking the case.

Beside the bodies of three murder victims lies a copy of the ABC Railway Guide.

Lucy Crale hires Poirot to solve the murder of her father sixteen years before, and Poirot finds a number of possible suspects who are still alive.

Matthew Davenheim, a rich banker, disappears on a walk from his country house to the village post office, and Inspector Japp of Scotland Yard is put onto the case. Poirot, who has developed an interest in conjuring tricks, bets Japp five pounds that he can solve the mystery without leaving his apartment.

Poirot is summoned to Marsdon by the owner of a country inn there to solve a murder. But the inn-keeper is a would-be thriller writer, and to Poirot's dismay the murder turns out to be fictional. Thankfully, though, there is soon a real (if seemingly supernatural) murder at the big house. Things get even more interesting when a young wife claims that a tree in her garden is haunted by a laughing ghost, and there are also signs of black magic from East Africa. Poirot lays a clever ambush to smoke out the killer,confident that he or she will turn out to be human.

Suggestions of a Communist conspiracy cast suspicion on a murdered woman's Russian servant. Meanwhile, Poirot has a rose named after him, and a ceremony at the Chelsea Flower Show makes him the centre of attention. Hastings receives a packet of seeds and develops hay fever.

Poirot's Christmas is interrupted by Simeon Lee, who believes his life is threatened. Simeon is soon killed and his diamonds stolen.

Poirot investigates a strange and gruesome murder of an elderly psychiatrist. Ariadne Oliver is pressed to try and uncover the truth behind two decade-old deaths. They soon find out that their separate investigations are linked and work together to try and solve the mystery.

In an effort to recover his confidence after a rare professional failure, Poirot sets off for the Swiss Alps in pursuit of a missing maid.

Hercule Poirot accompanies his friend Captain Hastings on a weekend shooting party at the home of Harrington Pace, but he isn't having a very good time. He comes down with the flu and takes to his bed but when Pace is shot dead in his study, he rises to the occasion to assist Inspector Japp in solving the case.

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.

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.

Ariadne Oliver is asked to devise a murder hunt for a Devon fête, but her sense of foreboding summons Poirot to the scene. Her fears are realized when, during the fête, the girl playing her murder victim winds up well and truly murdered.

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

Poirot discovers a murder in his own block of flats, and goes on the trail of boisterous neighbours and strange nocturnal noises in the lift shaft.

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.

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.

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.

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

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.

Hercule Poirot's solicitor, Gilbert Entwhistle, asks Poirot to help solve a riddle and a murder.

Three single girls share a London flat. The first works as a secretary; the second is an artist; the third, who comes to Poirot for help, disappears believing she is a murderer.

When a vicar chokes to death on a cocktail while attending a party held by actor Sir Charles Cartwright, Poirot initially dismisses the idea of murder but reconsiders when another guest dies in the same manner.