The tale tells the story of Rev. Justin Somerton, a scholar of Medieval history, who tells a rector the tale of how, while searching an abbey library he found clues leading him to the hidden treasure of a disgraced abbot.
In creating his adaptation, Bowen changed a number of elements of M.R. James's story, such as including another character, Lord Peter Dattering (Paul Lavers) as Somerton's protégé, with whom he shares his investigation. The story is not told in flashback, and also includes a scene in which Somerton exposes two fraudulent mediums, which acts as a demonstration of Somerton's rational approach to the supernatural.