In order to assassinate the mysterious principal of Superman High School, Jack of Hearts, disguised as Jack Chen, an ordinary human exchange student, infiltrates into the isolated Superman High School. He is accidentally assigned to Class F, the worst class. A group of problematic students with powerful superpowers make our strongest killer Jack of Hearts suffer a lot. Every single day is a frenzy and a life-threatening routine and the plan to assassinate the principal seems to be out of reach.