In February 1915 the Great War is still raging on the Western Front but back in Westminster a policeman is shot dead. At first, Hardcastle believes the murderer to have been a disturbed burglar. But then, there is another killing – the beautiful wife of a Royal Flying Corps Officer – on whose doorstep the first victim was killed.
As enquiries continue, attention focuses on an antiquarian bookseller, a struggling artist, a reporter and even officers of the Royal Flying Corps. Hardcastle must uncover a tangle of lies, emotions and betrayals before he can get to the truth.