The main attraction in Ahrensburg Castle is the smart, popcorn-loving ghost Schubiduu..uh. One day, Schubiduu..uh moves out because the castle administration has issued a popcorn ban. Since then, Schubiduh has been living in the attic of the Krüger family, because the siblings Jenny and Simon are his best friends. But soon the clever ghost is homesick for his old castle. Luckily for Schubiduu..uh, the ban on popcorn in the castle has just been lifted and so the ghost moves back into his old abod...