Finally summer vacation! Paula and Ruben eagerly dive into building their own treehouse. It’s going to have two floors and a rooftop terrace! Good thing their father is a carpenter. Bad thing is that he suddenly invites the new neighbor boy to help build the treehouse. They don’t even know this Marc! And now they have to share their treehouse with him? Luckily, it quickly turns out that the new neighbor isn’t so bad after all. He may not be able to hear anything without implants, but he can read lips perfectly. And that comes in quite handy when they unexpectedly get on the trail of a jewel thief...