Eleventh century Cambridge is rocked by a series of brutal murders. Called out to attend a body found on a lonely stretch of river bank, its throat torn out, apprentice healer Lassair is sceptical of the sheriff's verdict that this was the result of a wild animal attack. But when a second body is discovered, similarly mutilated, rumours engulf the town that the legendary demon known as the Night Wanderer has returned to wreak havoc.
Determined to stop the fear spreading and prove that the killer is human, Lassair and lawman Jack Chevestrier investigate. If they could only find out what links the victims, they would be one step closer to discovering the Night Wanderer's identity - and what it is he really wants. But when the killer turns his sights on Lassair herself, can she survive long enough to find out?