What's Christian About Narnia?
There's that death and resurrection of Aslan, for one thing. But that's only the beginning.
The entire Chronicles follow biblical contours. If in "The Lion, the Witch, and the Wardrobe" we have a retelling of Christ's suffering, death, and resurrection, the subsequent Narnia stories tell about the children's adventures in Narnia--their adventures, that is, during the time between Aslan's redemption of Narnia, and his final victory. This is, from the Christian viewpoint, the very same in-between time in which we are living now.
That final coming is reckoned in "The Last Battle," the last book of the Chronicles, which describes the ultimate battle between good and evil, and the final triumph of Aslan. As David Downing has pointed out in his marvelous study "Into the Wardrobe," the very opening of the book sets an apocalyptic tone: "On the last days of Narnia." Echoing the foretelling of the end-times in The Gospel of Matthew and the Book of Revelation, "The Last Battle" depicts the children dying in London and being received at a fabulous banquet by Aslan. Lewis's depiction of Aslan's folding all of history and culture into his kingdom never fails to give me chills:
The things that began to happen...were so great and beautiful that I cannot write them. And for us this is the end of all the stories, and we can most truly say that they all lived happily ever after. But for them it was only the beginning of the real story. All their life in this world and all their adventures in Narnia had only been the cover and the title page: now at last they were beginning Chapter One of the Great Story, which no one on earth has read: which goes on forever: in which every chapter is better than the one before.