Following an acclaimed debut outing, Harry Fox, an MI5 Watcher, now suspended, and his associate Stella Fry are reunited during Britain's darkest hour in this gripping espionage thriller.

April 1940, and Britain is in turmoil. Chamberlain's government is faltering, and a German invasion may be only weeks away.

A body, wearing the uniform of a Luftwaffe captain, is found in the grounds of Trent Park - a stately home and now a prison to house high level German POWs. Trent Park's true purpose, however, is intelligence, gathered covertly from prisoners by secret listeners.

The morning after the discovery of the body, one of the listeners goes missing, along with a gun from the firing range. Horrified that this could blow the highly confidential operation wide open, the missing man must be tracked down.

Cue Harry Fox, a former MI5 Watcher, now suspended. He is desperate to assist the war effort but he's over the conscription age. Then his former boss gets in touch with a job for him, to track down the missing man. But, he stipulates, it must also involve Harry's former associate, Stella Fry.

Stella returns home from work in the blackout to find a crowd outside her flat. She is told that a young woman in the building has had a fatal accident. The dead woman is called Stella Fry. Outraged, Stella suspects that this is the work of her erstwhile friend, Harry Fox. But why on earth would he go to such lengths to contact her?