Felix's school is haunted again, only this time it's not the benevolent spirit of school founder Otto Leonhard and the nuisance he caused, but the hated and long-since dead Director Hulda Stingbeard. A coincidence causes the former shrunken and skeletonized school principle to rise again. When she manages to return to real life she almost defeats Otto Leonhard, manages to shrink Dr. Schmitt-Gössenwein and Felix' parents, and takes over the school. It takes Felix, Ella and their gang to set the levers in motion to save the school and bring Dr. Schmitt-Gössenwein and his parents back to their original size again.
Already having a hard time adjusting at his new school, things take a turn for the bizarre for eleven year old Felix when he accidentally shrinks his strict principal to only fifteen centimetres in height!