Poirot er ikke særlig entusiastisk, da han af Mrs Todd får til opgave at løse mysteriet om en forsvunden kokkepige. Da fru Todd pludselig tager Poirot af sagen, bliver han fornærmet og indser hurtigt, at det hele ikke er så uskyldigt.

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.

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.

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 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 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.

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.

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?'

Millionaire business man Benedict Farley, a well known eccentric, consults Poirot about bad dreams he has been having. Mr. Farley has dreamed repeatedly of killing himself. Sadly, he does not follow Poirot's advice. When Farley is found dead, Poirot fails to believe that it is suicide and suspects a murder plot relying on hypnosis.