The main character, Aki Jouji, is a social studies teacher at Gokuraku Private High School. A former yakuza, Jouji was forced to become a teacher by the gang leader, and he sometimes acts out of character and pulls out a gun. When he takes off his sunglasses, his eyes look as cute as that of a kewpie doll, giving him the nickname "Kewpie from Hell." He is feared by the yakuza, and is always struggling to keep Ms. Shiratori, whom Jouji is in love with, from finding out about his past as a gangster.