A young English priest, Christopher Fairfax, makes his way on horseback from the cathedral city of Exeter to the far-flung village of Atticott St. George to conduct the burial of the local parson. The wild moorland is nearly devoid of people. The few he encounters are wretched in circumstance and darkly suspicious. He must reach the village before sunset or risk the consequences of breaking the nightly curfew. Yet when he arrives in the hidden valley, his unease only increases. Settling down for the night, he discovers that the old priest had a library of books that are banned as heretical, along with the collection of antiquities it is illegal to possess. Was his death - near an ancient monument known locally as the Devil's Chair - really an accident, or an act of murder? Until this moment, Fairfax has never known doubt. His faith in the Church and its teachings has always been unquestioning. But over the next six days everything he believes - about himself, his faith, the very history of the world - will be tested to the brink of destruction.