In A Dying Fall, forensic archaeologist Ruth Galloway investigates the death of her old university friend and fellow archaeologist, Dan Golding, who died in a house fire. The death takes on a sinister cast when Ruth receives a letter from Dan written just before he died.

Ruth travels to Blackpool to investigate, wary of encroaching on DCI Harry Nelson's home ground. Soon Ruth is embroiled in a mystery that involves the Pendle Witches, King Arthur, and – scariest of all – Nelson's mother. There are forces at work in the town that threaten all that Ruth holds dear.

It soon becomes apparent that the fire was no accident and seems to be linked with Dan's recent discovery of the possible bones of the legendary King Arthur.