Lucy Angkatell invites Hercule Poirot to lunch. To tease the great detective, her guests stage a mock murder beside the swimming pool. Unfortunately, the victim plays the scene for real. As his blood drips into the water, John Christow gasps one final word: 'Henrietta'. In the confusion, a gun sinks to the bottom of the pool.
Poirot's enquiries reveal a complex web of romantic attachments. It seems everyone in the drama is a suspect – and each a victim of love.