What is the exposition in chronicles of Narnia?

The exposition in The Chronicles of Narnia: The Lion, the Witch and the Wardrobe introduces the four Pevensie children, Peter, Susan, Edmund, and Lucy, as they are sent away from London during World War II to live in the countryside with an old professor. The professor's house is located near a large wardrobe, which Lucy discovers is a portal to the magical world of Narnia, where she meets the talking faun, Mr. Tumnus. Mr. Tumnus tells Lucy about the evil White Witch, who has ruled Narnia with an iron fist for many years and has made it always winter but never Christmas. Lucy returns home and tells her siblings about Narnia, but they do not believe her.

However, when all four children enter the wardrobe, they find themselves transported to Narnia and learn that Lucy's stories were true. They meet various talking animals and creatures, including the wise old lion, Aslan, who is the rightful ruler of Narnia and the only one who can defeat the White Witch. Aslan tells the children about the prophecy that they will free Narnia from the White Witch's rule, and the children begin their journey to find Aslan and fulfill the prophecy.

The exposition also sets the tone and atmosphere of the story, creating a sense of wonder, excitement, and danger. It immerses the reader in the magical world of Narnia, where the children embark on an epic quest filled with adventure, courage, and self-discovery.