The story follows the “strongest juvenile delinquent,” Oga Tatsumi, who is a first year in “Ishiyama High,” a school for delinquents. The story starts as he is telling the story of how he found the baby to his best friend Furuichi Takayuki. One day while doing laundry by the river (actually, taking revenge on people trying to kill him in his sleep), he sees a man floating down it. He pulls him to shore and it splits in half which reveals a baby boy inside. This boy is the son of the great demon king and he has been chosen as the one to raise it with the baby’s maid Hilda. The story follows his life with the child and at the delinquent school.
男 鹿辰巳，石矢魔高中的不良学生，打架无败记录，因此被周围人称为恶魔。某次在河边打架的时候遇见了从上游漂来的大叔，男鹿把大叔带上岸之后大叔却突然分成 两半，惊魂未定之余又发现了大叔体内有个婴儿，谁知道这个小婴儿竟然是来自魔界未来的魔王——魔王的儿子！男鹿也莫名其妙的成为魔王的父亲，从此开始了本 来就不平凡的生活。