Robert Colwan, a clergyman's son, is so confident of his salvation as one of the Lord's elect that he comes to look on himself as a man apart, unhindered by considerations of mere earthly law. Through Robert's own unforgettable account, we follow the strange and sinful life into which he is led by a devilish doppelganger - a life that will finally lead him to murder. Steeped in the folkloric superstitions and theological traditions of eighteenth-century Scotland, this macabre and haunting novel is a devastating portrayal of the stages by which the human spirit can descend into darkness.