Set in the 13th century court of England's King Henry III the novel centers around the wedding of the title character. The wedding is interrupted by a merchant who claims to have been wronged by Gaston, in that Gaston murdered his kinsman. Henry is forced to hold a trial to determine the validity of the claims. The plot is further complicated by the machinations of an abbot who tries to suppress the truth, and by ghosts who want to expose the truth.
The book is described as a "drawn out and sometimes rambling, the plot lacking in impetus", but is notable as being the last novel to be both written (circa 1802) and published (in 1826, posthumously) by Mrs Radcliffe. The book is noteworthy for its detailed descriptions of locations.