The First Period is narrated by Gabriel Betteredge, the House-Steward at Julia, Lady Verinder's estate. The date is May 22, 1850, and Franklin Blake, Lady Verinder's nephew, has just asked Betteredge to narrate the events surrounding the loss of the Indian Diamond at Lady Verinder's Yorkshire house in 1848. The narrative is to serve as a record of the facts, to clear the characters of innocent people who have been suspected in the theft. Blake has enlisted the people connected with the Diamond to narrate the events "in turn—as far as our own personal experience extends, and no farther."
Betteredge agrees to write the narrative. Before he begins he has been consulting Robinson Crusoe for prophecy and guidance. For many years, Betteredge has always consulted the novel in times of need. The novel now warns of the folly of beginning a task without knowing how difficult it will be. Betteredge worries about the difficulty of remembering and narrating all of the events surrounding the Moonstone and its theft.