A seemingly harmless prank involving an excessive number of alarm clocks leads to a series of high-stakes murders and the discovery of a secret society. Lady Eileen 'Bundle' Brent, a spirited young socialite, finds herself entangled in a web of international intrigue after a friend dies under suspicious circumstances at a country house party. She must navigate a landscape of hidden identities, clandestine meetings, and dangerous adversaries to uncover the truth behind the mysterious 'Seven Dials'. The narrative unfolds through a blend of lighthearted social comedy and tense investigative sequences, tracking Bundle's efforts to outmaneuver those who wish to keep the organization's existence concealed.

This novel is widely recognized as a classic example of Agatha Christie's early, more adventurous style of detective fiction. Critics often highlight the shift from her traditional locked-room puzzles to a more fast-paced, thriller-oriented narrative structure. Readers frequently note the charm of the protagonist, Bundle Brent, who brings a distinct energy to the investigation compared to the author's more methodical detectives. The work is generally regarded as an entertaining, lighthearted entry in the Christie canon that successfully balances suspense with social satire.