The novel is set primarily in the world of Narnia, decades after The Voyage of the Dawn Treader there but less than a year later in England.[a] King Caspian X is now an old man, but his son and only heir, Prince Rilian, is missing. Aslan the lion sends two children from England to Narnia on a mission to resolve the mystery: Eustace Scrubb, from The Voyage of the Dawn Treader, and his classmate, Jill Pole. In the frame story, Eustace and Jill are students at a horrible boarding school, Experiment House.
