In 1360 a deputation from Cambridge ventures to the Suffolk town of Clare in the hope that the wealthy Elizabeth de Burgh has left a legacy to Michaelhouse. Yet when they arrive they discover that the report of her death is false and that the college seems destined for bankruptcy.

Determined to see if some of its well-heeled citizens can be persuaded to sponsor Michaelhouse, Matthew Bartholomew, Brother Michael and Master Langelee become enmeshed in the town's politics. They quickly discover that a great many other people in Clare have recently met untimely deaths. These killings, combined with the arrogance Lady de Burgh has shown over the refurbishment of the church and the grotesque behavior of some of her entourage, have created a dangerous restlessness in the town: an atmosphere intensified when yet more murders occur.

One of the victims is a fellow traveler of the Michaelhouse contingent, and Matthew Bartholomew and Brother Michael feel honor-bound to identify his killer. It is a hunt which takes them deep into Clare's murky foundations and which threatens their own survival as well as that of their beloved college.