Hercule Poirot’s relaxing holiday on the Cornish coast takes an unexpected turn when he meets young and pretty Nick Buckley. For it seems to Poirot that too many accidents have been happening to Nick and he, with the help of Captain Hastings, is determined to prevent another accident becoming a tragedy.

There is a full complement of characters populating the cozy English village of King's Abbot, and, among them, the redoubtable Hercule Poirot and his little grey cells. When the murder happens, there are all kinds of clues to mislead us, and the listener gets so involved with these red herrings (or not) that the very simple truth eludes the puzzler.

Poirot visits the sleepy English village of Warmsley Vale to check into the background of Gordon Cloade, supposedly a victim of the London Blitz. He had married an attractive young widow, now the sole possessor of the Cloade family fortune. The deceased's sister-in-law told Poirot that "spirits" informed her that the widow's first husband is still among the living. This raises suspicions about Cloade's death.

Aboard a Nile steamer, Hercule Poirot meets Linnet Doyle, a woman who appears to have everything: youth, beauty, wealth, and a loving husband. But the husband was stolen from her friend Jacqueline de Bellefort, who has been haunting the newlyweds’ path, showing up to wreak havoc in their plans. They’ve secretly booked passage on the steamer to escape, but still, tragedy strikes: Linnet is shot through the head. As the complications multiply, Poirot and his little grey cells are faced with nothing but airtight alibis.

Poirot's little gray cells are activated when he receives a letter from an elderly woman concerned about her safety - two months after her death. Soon he and Hastings visit Little Green House and meet the late Miss Arundell's multiple relatives, all of whom had opportunity and motive to benefit from her death.

Actress Jane Wilkinson approaches Hercule Poirot and pleads with him to speak to her husband, Lord Edgware, who is refusing to divorce her. The next morning Lord Edgware is found murdered and witnesses tell Poirot that Jane Wilkinson was the last person to see him alive. However, Jane was at a dinner party miles away at the time with twelve other guests who will testify to her being there.

When Tommy and Tuppence Beresford move to a quiet English village, they were looking forward to a peaceful retirement. But, as they soon discovered, their rambling old house held both secrets and dangers.

Lucy Angkatell invited Hercule Poirot to lunch. To tease the great detective, her guests stage a mock murder beside the swimming pool. Unfortunately, the victim proves to play the scene for real.

What a little gem! Each member at a Tuesday night get-together tells a tale of mystery, preferably one he or she has personal knowledge of, and the rest of the crowd tries to figure out the solution. As Miss Marple is among them, looking harmless with her knitting, the rest hardly stand a chance...

An emaciated stranger approaches Hercule Poirot, shouts a warning about "the big four" and drops dead. Who knew Poirot's inquiry into the man's odd behavior would lead to an underground laboratory, an insane asylum, and rumors of a secret weapon?

The Grim Grotto begins, as ever, where the last instalment, The Slippery Slope, ends. Violet, Sunny and Klaus are cascading down the grey waters of the Stricken Stream in a toboggan and again hurtling towards inevitable doom.