Welcome to the school for thieves! "Here we will teach you 'the bad' so that one day, using your experiences and skills, you can do good and restore order to the world." It is Gabriel's second year at Crookhaven. Right from the start, it requires a lot of work: Burglary is tough, and a new diving course called Retrieval has been added. One day, Gabriel and his friends learn about the Maravel Labyrinth, a maze of obstacles hidden deep beneath the lake, almost forgotten by everyone at the school. At each obstacle, a trickster skill is tested; the challenges, all together, are impossible to overcome. But "impossible" has never stopped Gabriel's gang, especially now that they know there is something at the center of the labyrinth, something that all the members desperately want...