"The Battle for WondLa" is a science fiction novel by Tony DiTerlizzi, continuing the story of Eva Nine, a young girl raised in a high-tech underground world. After escaping to the surface, she discovers a vibrant but dangerous alien landscape filled with unique creatures and challenges. In her quest to find her true home, Eva encounters allies and enemies, including the mysterious Rovender Kitt, who helps her navigate this new world. The story explores themes of friendship, identity, and the struggle between nature and technology as Eva fights to protect her newfound friends and the land of WondLa.