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

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.

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.