Set in Cornwall in 1910, this novel centers on the death of the Viscount of Tithe Hall, who is found murdered in a sealed room on a remote tidal island during preparations for the anticipated passage of Halley's Comet. Suspicion falls on Stephen Pike, a recently hired under-butler with a troubled past. Assisted by an elderly member of the household, he becomes involved in uncovering the circumstances surrounding the crime. As the investigation unfolds within the confines of the country house, long-standing conflicts and hidden relationships emerge. The novel combines elements of historical setting with a classic locked-room mystery