Here's why:
* Mystery: The story revolves around a missing girl and the protagonist's attempts to uncover the truth, leading to twists and turns.
* Thriller: The novel builds suspense and tension as the protagonist faces danger and tries to stay one step ahead of the unknown.
* Young Adult: The main character is a teenager, and the themes and language are geared towards a younger audience.
While the novel has elements of other genres, like romance and supernatural, the core of the story lies in the mystery and suspense, making it primarily a young adult mystery/thriller.