This is the fifth book that Lewis wrote in his acclaimed Chronicles of Narnia series, but chronologically, it is the third title.
During the Golden Age of Narnia, when Peter is High King, a boy named Shasta discovers he is not the son of Arsheesh, the Calormene fisherman, and decides to run far away to the North—to Narnia. When he is mistaken for another runaway, Shasta is led to discover who he really is and even finds his real father.