A long tress of hair, still attached to a human head, is the grisly discovery that Brother Cadfael witneses during the ploughing of the Potter's Field... and the pointer to an unlawful deed.

The tenant potter had only recently entered the Benedictine Abey of St Peter and St Paul, to become a monk, after fifteen years of marriage, and had left behind him a wife bitterly opposed to his departure. Rumour had it that the wild, beautiful Welsh woman had returned to her homeland - with or without another lover, who could tell?

But the discovery of a corpse on Abbey land raises all sorts of questions, and ones that impel Brother Cadfael to leave the tranquility of the herbiary in order to piece together some cryptic clues and solve a baffling crime. The explanation, when it comes, is as totally satisfying as it is unexpected, for as the monastic sleuth proclaims, 'God's justice, if it makes no haste, makes no mistakes.'