Lewis, The Lion, the Witch, and the Wardrobe (The Chronicles of Narnia, Book 1)

They open a door and enter a world Narnia … a land frozen in eternal winter … a country waiting to be set free. Four adventurers step through a wardrobe door and into the land of Narnia — a land enslaved by the power of the White Witch. But when almost all hope is lost, the return of the Great Lion, Aslan, signals a great change … and a great sacrifice.