It is Scotland in the early eighteenth century. Fear and superstition grip the land. Robert Wringhim, a boy of strict Calvinist upbringing, is corrupted by a shadowy figure who calls himself Gil-Martin. Under his influence Robert commits a series of murders which he regards as 'justified' by God under the tenets of his faith.

Hogg's masterpiece is a brilliant portrayal of the power of evil and a scathing critique of organised religion. Superbly crafted and deftly executed, it resists any easy explanation of events: is this stranger a figment of Robert's imagination, or the devil himself?