After Karukozaka High School is transported to the Expanse, demons roam the hallways among frightened students. The protagonist encounters one of these demons - a friendly Jack Frost. This particular Jack Frost is known as "Hee-Ho-kun" and he seems to have acquired a school uniform from somewhere. He states that he loves attending school and that all good children should use 'Hee-Ho' in their polite speech, and then he offers to join the protagonist's party.