book title: Thea sisters and the secret city by Thea Stilton published by Scholastic
so the book is about one of the sisters. One of them is visiting her very close sister, Maria, and their is the king's son Ganzolio, who is missing and they go on a trip to find this place called the secret city.
I really liked this book because they were committed to working together. And in one part of the book they caught 3 criminals! The end is surprising and very good. The book is a series, related to the series of Thea's brother Geromeno who also has a lot of adventures but the complete opposite of her.
