In Autumn of 1093, Lassair encounters a veiled noblewoman on the quay at Cambridge, set on by an angry mob. She has no idea that the woman, alone but for her infant child, brings both mystery and peril. Then a devastating flood hits the fens, and among the wreckage washed up Aelf Fen is a body. Lassair, in the company of a sheriff's officer, wonders if she is dealing with murder. Meanwhile, in the south, Lassair's beloved Rollo is moving with relief...

Called out to attend a body found on a lonely stretch of river bank, its throat torn out, apprentice healer Lassair is skeptical of the sheriffs verdict that this was the result of a wild animal attack. But when a second body is discovered, similarly mutilated, rumors engulf the town that the legendary demon known as the Night Wanderer has returned to wreak havoc.

"Forensic archaeologist Ruth Galloway changed her life -- until a convicted killer tells her that four of his victims were never found, drawing her back to the place she left behind"-- Convicted murderer Amyas March offers to make DCI Nelson a deal. Nelson was always sure that March killed more women than he was charged with, and March offers to show Nelson where the other bodies are buried -- but only if Ruth Galloway will do the digging. When she...