England, 1176. Aelred Barling, esteemed clerk to the justices of King Henry II, is dispatched from the royal court with his young assistant, Hugo Stanton, to investigate a brutal murder in a village outside York. The case appears straightforward. A suspect is under lock and key in the local prison, and the angry villagers are demanding swift justice. But when more bodies are discovered, certainty turns to doubt - and amid the chaos it becomes clear that nobody is above suspicion.

harles II is well established at White Hall Palace, his mistress at hand in rooms over the Holbein bridge, the heads of some of the regicides on public display. London seethes with new energy, freed from the strictures of the protectorate, but many of its inhabitants have lost their livelihoods. One is Thomas Chaloner, a reluctant spy for the feared secretary of state, John Thurloe, and now returned from Holland in desperate need of employment. 

Hugh of Singleton, fourth son of a minor knight, has been educated as a clerk, usually a prelude to taking holy orders. However, feeling no certain calling despite a lively faith, he turns to the profession of surgeon, training in Paris and then hanging out his sign in Oxford. A local lord asks him to track the killer of a young woman whose bones have been found in the castle cesspit. She is identified as the impetuous missing daughter of a local blacksmith, and her young man, whom she had provoked very publicly, is in due course arrested and sentenced at the Oxford assizes.

It's 1194, and Sir Faucon de Ramis, the shire's newly appointed keeper of the pleas, must do his duty and make an official declaration of the cause of a miller's death. Saddled with a clerk who names Faucon his "penance", the shire's first crowner must thread the tangled relationships between the sheriff, the village of Priors Holston, and the priory that once ruled it. As a simple task takes a turn to the political, what seems obvious isn't, and what appears safe turns out to be more dangerous than he could imagine. 

The much-feared and hated Eudo - the Lord Bishop of Winchester's clerk - is bludgeoned to death in Pershore Abbey and laid before the altar in the attitude of a penitent. Everyone who had contact with him had reason to dislike him, but who had reason to kill him? The Sheriff of Worcestershire's thief taker, wily Serjeant Catchpoll, and his new and unwanted superior, Undersheriff Hugh Bradecote, have to find the answer. And as the walls of the abbey close in on the suspects, the killer strikes again....