Penelope Crook surprises Gabriel and the rest of the gang at the start of their second year at Crookhaven with a startling secret: deep beneath the lake lies an underground labyrinth that was once used for the most difficult school exams. But as it was far too dangerous, it was shut down and forgotten. But there are clues that the Nameless Ones, the most ruthless criminal gang in the world, have taken advantage of it. The friends secretly follow this trail. But the path to the centre of the labyrinth leads past seemingly insurmountable obstacles that put each of their crook skills to the test. They are not only confronted with all kinds of impossible puzzles, but also with the question of how far they are prepared to go to reach their goal. Narrator Nico-Alexander Wilhelm takes us back to the mysterious world of the outlaws and through Gabriel's second school year full of challenges and twists and turns.