The sudden disappearance of the incoming head of MI6 forces a retired operative back into the shadows to prevent a catastrophic intelligence leak. Thomas Kell, a man haunted by his past in the service, must navigate the labyrinthine bureaucracy of British intelligence to locate Amelia Levene before the media exposes her absence. The narrative follows a tight, procedural structure, tracking Kell as he reconstructs Levene's final days through fragmented evidence and clandestine interviews. He faces opposition from both external threats and the internal politics of an agency desperate to maintain its reputation.

This novel is widely recognized for its grounded approach to the spy genre, moving away from high-octane action toward the gritty reality of intelligence work. Critics frequently highlight the author's ability to capture the bureaucratic claustrophobia of MI6, earning the work significant acclaim including the CWA Ian Fleming Steel Dagger. Readers often note the complexity of Thomas Kell as a protagonist, appreciating his weary, pragmatic outlook on the world of espionage. The narrative is praised for its meticulous attention to detail and its refusal to rely on common genre tropes, establishing it as a notable entry in contemporary British crime fiction.