From the introduction:
After the usual disorientation that followed the end of your previous Jump, you look around to find yourself in a small Oxford study, the walls lined with old books, the table set with fine china and silver. It looks like you've caught your Benefactor in the middle of a tea party. Strangely, her only other guest seems to be an enormous Lion. You find yourself instinctively capitalizing that word. She introduces him as her friend Aslan, and explains that he is going to be your gracious host for the next decade of your adventures.
A land of hope and wonder. A land of oppression and tyranny. A land of danger and adventure. A land of blatant Christian allegory. However you choose to see it, you will be spending the next ten years in the world of Narnia.