June 1918. A patrolling constable discovers the body of Georgina Cheney, wife of a naval commander, in the basement area of a house in Westminster. At first it is thought to be suicide or even a tragic accident. But as Divisional Detective Inspector Ernest Hardcastle of the A or Whitehall Division of the Metropolitan Police begins to investigate – ably assisted by Detective Sergeant Charles Marriott – they soon discover a different story. It is clear that the woman was murdered, and revelations about the victim’s previous life in Malta arouse Hardcastle’s interest.

But things are destined to get even more complicated for Hardcastle, when he is assigned two further murder cases by Detective Chief Inspector Frederick Wensley, head of the CID at New Scotland Yard. Could they be connected? This may be a puzzle too tricky even for Hardcastle to solve . . .