A new housekeeper at a country estate witnesses a suspicious death, and Inspector French must unravel the truth before another tragedy occurs. Anne Day arrives at Frayle, the home of Mr. Grinsmead and his invalid wife, only to find her premonitions of unease confirmed by a sudden death. As the police quickly form conclusions, Inspector French is called in to lead the investigation. The narrative alternates between Anne's perspective, offering an insider's view of the household, and French's methodical approach, providing an external examination of the clues.

This novel is presented as a classic crime mystery, celebrating the centenary of Freeman Wills Crofts, known as 'The King of Detective Story Writers'. The narrative structure, which switches between the perspectives of the new housekeeper and Inspector French, is designed to provide both an inside and outside view of the investigation. The premise suggests a complex and elaborate puzzle that Inspector French must meticulously unravel. The inclusion of a potential second tragedy heightens the suspense and urgency of the mystery.