In the chilly, damp Autumn of 1144, two groups of visitors seek the hospitality of the Abbey of Saint Peter and Saint Paul, and Brother Cadfael fears the trouble has come in with them. Among the first arrivals is Brother Tutilo, a young Benedictine with a guileless face and- to Brother Cadfael's shrewd eyes- a mischievous intelligence. The second group, a ribald French troubadour, his servant and a girl with the voice of an angel, seems to Brother Cadfael a catalyst for disaster.

All of Cadfael's fears become manifest as rising flood waters endanger the abbey's most sacred relic, the remains of Saint Winfred. When the bones disappear and a dead body is found, Brother Cadfael knows that carnal and spiritual intrigues are afoot. Now, in a world that believes in signs and miracles, Brother Cadfael needs his prayers answered- as well as some heavenly guidance to crucial clues- to catch a killer hell-bent on murder.