Surrey Hills, 1865
Scotland Yard detectives, Inspector Leslie and Sergeant Pashtine, are called in when a body is discovered in a beautiful valley in the Surrey Hills where a new railway is being built. The land between two hills is owned by two local men, an MP and a Naval gun designer, Mr Reynolds, who have houses on their respective hills. The dead body is that of Mr Reynold's son, who was believed to have gone to India, but never left the valley.

Tensions rise between the local villagers and the navvies who are building the railway. The valley woods had been a mysterious place, where century old rituals took place. Now it is corrupted by more modern forces, but the real problem for the detectives is the complex characters of the victim's mother and father, and what they think they know about what happened to their son. Events start to escalate with the botched sea trials of Mr Reynold's new gun, and the pressure to finish the railway in time for the June races at Epsom.