On the eve of the Great War in 1914, a body is found in the lake at St James' Park. What initially appears to be a robbery becomes more complex when it is discovered that the victim is a servant oat one of London's prestigious gentleman's clubs.

Hardcastle's enquiries reveal that the clubs members - and some of its staff - are not all they purport to be. Discovering thieves, adulterers and a blackmailer along the way, and despite attempts to prevent him uncovering the truth, the persistent DI Hardcastle eventually makes an arrest.