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.

The monks of Shrewsbury go to Wales to recover the bones of St. Winifred. But their attempted bribery of the Welsh puts them at odds with the local residents—and when the local landowner is found murdered, the monks are regarded as prime suspects.

The recently-widowed wife, Judith Perle, of a rich merchant becomes the object of interest for the men of Shrewsbury. But then a monk and one of her suitors are murdered.

Cadfael puts Hugh Beringar to the test, and Hugh has to choose between loyalty to the king and friendship with Cadfael. Meanwhile, at the annual St. Peter's Fair in Shrewsbury, townspeople come into conflict with the Abbey's officers and with visiting merchants. A curfew is ordered, but not fully observed—then Cadfael finds he has a murder to solve.

Cadfael is on a double murder hunt following the deaths of a pregnant girl and the priest who refused to take her confession.