Prince Caspian (Chronicles of Narnia, Bk. 4)

Peter, Susan, Edmund, and Lucy are suddenly pulled into Narnia from their own land of England by a distress call from Prince Caspian. It has been hundreds of years since the time described in The Lion, The Witch, and the Wardrobe, when the children reigned over the land as benevolent Kings and Queens. Now most of the Talking Beasts and enchanted creatures who once lived there in peace have been killed or frightened into hiding. Only Caspian and the rulers of Old Narnia, with the help of the great Aslan, can liberate Narnia and make it safe for its rightful inhabitants.