September 1143. Sergeant Catchpoll hopes a fire at a Worcester silversmith's is just an accident, but when there is a second fire, and a charred corpse is discovered, he has no choice but to call in the undersheriff, Hugh Bradecote, to help find the culprit.

With further fires, a hooded figure stalking the streets, and a possible murder that has gone undiscovered for some months, the duo have to work together to avoid getting more than their fingers burnt in this puzzling investigation.