Lucy Pevensie is the first character to discover Narnia in C.S. Lewis's The Lion, the Witch and the Wardrobe.
While exploring an old country house, Lucy enters a wardrobe and finds herself in a snowy wood. She meets Mr. Tumnus, a faun, who tells her that she is in Narnia. Lucy later returns with her siblings, but they initially doubt her account.
Her discovery begins the central adventure and establishes the book's movement between the ordinary world and the magical one. Lucy's openness and trust contrast with Edmund's early temptation by the White Witch and the older siblings' skepticism.
The Pevensie children are Peter, Susan, Edmund, and Lucy. In the story, their wartime evacuation from London brings them to the country house where the wardrobe is kept. Lucy is therefore both the first explorer and the character who first brings news of Narnia to the others.