À la fin des années 1980, Marcus Lopez, un jeune orphelin SDF, est admis au sein d'une mystérieuse école privée qui accueille la progéniture des criminels les plus dangereux de la planète. Dans cet établissement, les adolescents se voient enseigner l'art du meurtre, du combat ou toutes autres pratiques indispensables pour devenir le parfait criminel.

Sam Ashley, a graduate of 1965 class of Bret Harte High School, who was now a teacher at the school, served as the narrator describing what had happened to his fellow graduates in the decade since they had graduated.

Author Tarō Obika is an obsessed single father who loves his daughter so much, he decides to go to the same college. Nicknamed Gatarō, he was widowed when his wife died of an illness and has raised his only child Sakura all on his own.

Things are about to change drastically as Sakura prepares to enter a coeducational university after going to an all-girls school all her life. Worried sick, Gataro enrolls not only in the same school, but also in the same department, and the madness begins!

Unable to control his anxiety, he sticks his nose in her every business, from classes to extracurricular activities, parties, dating events, cultural festivals, part-time jobs, and everything else college kids do. But as the 40-year-old middle-aged dad gets involved in the youthful pursuits of Sakura and her colleagues, he finds himself enjoying life even more than them.

Set in the 80s, disillusioned orphan teen (Marcus) is accepted into a private elite academy training the next generation of youth assassins for the criminal underworld.