Maurice Allington, dissipated, cultivated, paradoxically engaging, is the modern landlord of a medieval coaching inn, The Green Man. As an old inn should, it has a persistent, long-quiescent ghost: Dr. Thomas Underhill, a 19th-century practitioner of the black arts and a sexual deviant suspected of two hideous murders. Alllington becomes the sole witness to the reappearance of Underhill in the hot summer of 1968 and is driven by a series of unpleasant incidents to bring about a climactic confrontation with the supernatural visitant.