A disillusioned journalist discovers a haunting physical connection to a disgraced ancestor that pulls him into a spiral of obsession and ancestral dread. After his marriage collapses, James Mangan retreats to his father's home, where he unearths a daguerreotype of a man who appears to be his exact double. This discovery triggers a compulsive investigation into the life of the 19th-century poet James Clarence Mangan, whose reputation for debauchery and madness begins to mirror Jamie's own unraveling psyche. The narrative follows Jamie's descent as he travels to Ireland to uncover the truth, facing both the physical isolation of the Irish countryside and the internal pressure of his own perceived failures. The story utilizes a third-person limited perspective to track the protagonist's increasing detachment from reality as he attempts to reconcile his identity with the dark legacy of his namesake.

This novel is widely regarded as a sophisticated entry in the gothic tradition, noted for its ability to blend psychological realism with a sense of encroaching dread. Readers and critics often highlight the author's precise prose and his skill in depicting the protagonist's slow disintegration. The book is frequently discussed for its thematic preoccupation with the burden of history and the ways in which the past can exert a tangible influence on the present. It remains a notable example of how the author uses the structure of a mystery to examine deeper questions of identity and artistic legacy.