"The Mixed-Up Files of Mrs. Basil E. Frankweiler" is a children's novel by E.L. Konigsburg that follows two siblings, Claudia and Jamie Kincaid, who run away from home. They decide to hide in the Metropolitan Museum of Art in New York City, where they explore the museum's treasures and enjoy a life of adventure. As they navigate their new surroundings, the siblings discover a mysterious statue of an angel and become intrigued by its origins. Their quest to uncover the truth leads them to the eccentric Mrs. Basil E. Frankweiler, who holds the key to the statue's secrets and their own journey of self-discovery.