Who would believe that the 12-year-old Felix turned his school's hated math teacher into a villain only 15 centimeters tall? He didn't know how he did it, but it seriously affected the life and death of his school. He has to change his teacher back to his original size, but what should he do? In a series of attempts and adventures, Felix became more and more brave and responsible. Not only did I better understand the teacher's good intentions in this adventure, but also gained the friendship from Ella.