Eustace and Jill are on the run from school bullies when Aslan suddenly calls them to Narnia. Caspian's son, Prince Rilian, has been missing for ten years and Aslan wants the children to find him. With the help of the Marsh-wiggle, Puddleglum, Eustace and Jill journey across giant country and into a strange underground world in their search for the lost prince. But in order to save Rilian, the friends must first battle a deadly evil that lurks below the surface of their beloved Narnia..