Because Sutcliff follows her medieval sources so closely, The Light Beyond the Forest is imbued with the atmosphere of medieval romance. Although the narrative moves from an initial incident whereby the knights learn that the Grail has appeared again in England to a final climax in which the three heroes visit the land of the Grail, the tale is told episodically, with frequent shifts of focus among the four major characters.

Sutcliff provides sufficient background throughout her story to introduce readers to the major characters of the Arthurian legends, yet her narrative moves quickly, with little authorial intrusion. Sutcliff adopts many trappings of the literary tradition of the medieval romance, including magic forests and ships, demons and angels who interact freely with human protagonists, spells and witchcraft, and a sense of the faraway in both place and time.