Renovation of a school founded by Richard de Revelle uncovers a partially mummified corpse hidden in the roof. The former sheriff blames Nicholas de Arundell, an outlawed knight living on Dartmoor who has strong reasons to hate him, but neither the victim’s identity nor the date of death is immediately clear.
A second killing forces John to find Nicholas before the sheriff’s men do. By tracing the school’s construction, the dispossession of the outlaw and the interests of those surrounding de Revelle, he discovers that the fugitive may be the only person able to explain why an old crime has produced new violence.