A year after returning home from Narnia, the children are waiting for a train when they are suddenly whisked to a strange land. They realize they are back in Narnia, but the area is unfamiliar to them. They come upon the ruins of a castle and eventually conclude that they are at their old home and that many years have passed since they lived there. Due to the time differences between the Narnian world and our world, it is now over a thousand years since their last visit.
Narnia has fallen on hard times: the holy and benevolent lion Aslan has not been seen in centuries, the false king Miraz has ascended the throne through treachery, and talking animals and trees are nowhere to be found. Prince Caspian, the rightful heir to the throne, has used Susan's horn - originally a gift from Aslan and now an ancient artifact - to summon the Pevensies back to Narnia. Together, they attempt to restore goodness to the world.
Once again, Lewis takes the reader into a world that is both magical and believable. This is a story of a world that has fallen from righteousness into wickedness. It is an attempt at redemption for the land, its rulers, and its people. Knowing Lewis's Christian roots, we can assume he was thinking of the rise and fall and rise of God's chosen people in the Old Testament when he wrote this book.
It is an enjoyable story, and it introduces the fearless talking mouse Reepicheep, who is one of my favourite characters in these Chronicles.