Georgia Strangeways infiltrates a clandestine fascist organization to thwart a plot to overthrow the British government. When her husband Nigel is away, Georgia discovers a dangerous conspiracy led by a charismatic and wealthy figurehead. She must navigate a web of deception and physical peril, relying on her wits to survive as she is hunted by the very group she sought to expose. The narrative follows her harrowing escape and eventual rescue by her father-in-law, Sir John Strangeways, as the stakes escalate from personal investigation to national security.

This novel is recognized as a significant entry in the golden age of British detective fiction, blending traditional mystery elements with the heightened tension of political espionage. Readers often note the sharp contrast between the domestic life of the protagonists and the dark, conspiratorial world of the antagonists. The work is frequently praised for its atmospheric prose and the clever integration of its literary title into the thematic core of the story. It remains a staple for those interested in the evolution of the thriller genre during the mid-twentieth century.