When one of her company falls ill on a return journey to Tyndal, Prioress Eleanor accepts lodging at a nearby manor. There, Master Stevyns's wife is having an affair, whilst the master's son and spouse are obsessed with sin and heaven. It is no surprise when someone's throat is cut. The sheriff does all he can to avoid offending the family rather than seeking the killer. Eleanor must discover the dark secrets before the murderer strikes again.