Cambridge, March 1354, and the cause of murder is once more on the mind of Matthew Bartholomew. . .

It is a time of division and denomination at the great university. The Carmelites and Dominicans are at theological loggerheads over the philosophy of nominalism, so much so that the more fanatical are willing to swap rational argument for a far deadlier form of debate. And when Carmelite friar Faricius is found stabbed, physician Matthew Bartholomew has to attempt to save his life while a stone-throwing mob clamours outside the window.

Bartholomew's skills are to no avail. He is too late to save Faricius, and Brother Michael, the university's senior proctor, has no choice but to launch a murder investigation. But then, with their inquiries barely begun, and with suspicions firmly pointing towards the rival Dominicans, a second tragic death is discovered. Will Walcote, Brother Michael's junior proctor, is found hanging from the walls of the Dominican friary.

The more Bartholomew and Brother Michael investigate, the more they find questions rather than answers. Why was Faricius found outside his friary, when he was not permitted to leave? How are the nuns at St Radegund's involved? Why was Walcote setting up clandestine meetings behind Michael's back? And who is negotiating between Cambridge and their great enemy, Oxford? The longer the inquiries go on, the more Bartholomew realises that the murders are less to do with high-minded principles, and more to do with far baser instincts. . .