Detective wanted! If you see things that others don't. If you enjoy uncovering secrets that others can't even sense, then come to the treehouse during the big break today. Olli has been working on his detective career for quite some time. But as everyone knows, anyone who wants to become a Sherlock Holmes also needs a Watson. And who better suited for that than the reader themselves? During the interview, it quickly becomes clear that Olli and the reader are on the same wavelength, but they don't have much time to get used to each other, as they hear someone shout: "Hey, stop the thief!" And just like that, they are right in the middle of their first case... An interactive puzzle fun that directly engages the reader and takes them into a world full of riddles, hidden pictures, word games, and number games.