In "The Lion, the Witch and the Wardrobe" by C.S. Lewis, Lucy discovers a hidden world called Narnia through a wardrobe in the Professor's house. Initially, her siblings, Peter, Susan, and Edmund, doubt her story about this magical land. However, once they eventually explore the wardrobe themselves, they enter Narnia and uncover a realm cursed by the evil White Witch.
Upon encountering Aslan, the Great Lion, the siblings realize they are part of a significant adventure to liberate Narnia from the Witch's dark magic. United in their courage, they join forces to confront the dangers ahead and strive to free the enchanted land from its tyranny.