* Annabel "Annie" Davies: The protagonist, a young girl struggling to adjust to life in a new town after her family moves there. She's imaginative, observant, and fiercely loyal to her friends.
* Frankie Harrison: Annie's new best friend, a girl with a wild spirit and a love for adventure. She's passionate, funny, and secretly insecure.
* Catherine "Cat" Harris: A somewhat shy girl who initially appears withdrawn but is revealed to be a deep thinker with a kind heart. She is close to Frankie and eventually becomes a friend to Annie.
While there are other important characters in the story, these three form the core friendship that drives the plot. Their adventures, secrets, and challenges as they navigate adolescence and their unique bond are the focus of the book.