Jakob, Nelli, and Marek are not exactly what you would call best friends. Now they are supposed to keep watch together at summer camp to get to know each other better. In the middle of the night, they suddenly hear suspicious noises. Strange tracks lead the children to the pirate museum and straight into the hands of a ruthless gang of burglars. Will the three of them manage to work together to escape the crooks? And will they succeed in unraveling the mystery of the famous pirate Nine-Eye? In their flight, they find themselves in a pirate fortress and deeper into a creepy labyrinth full of puzzles.