
Cadfael's novice, Brother Oswin, is found close to death, babbling about a woman. When a nun is found raped, murdered and encased in the ice of a frozen stream, Oswin is accused of murder. Cadfael tracks the nun's companion, Ermina Hugonin, and sets out to prove Oswin's innocence.

A rich priest is found killed, and the finger of suspicion points to a new monk at Shrewsbury Abbey. Meanwhile, a civil war raging around England is piling political pressures on the Abbot. Cadfael investigates the murder and uncovers a tangled web of dishonesty and nepotism.