The story follows the strongest juvenile delinquent, Oga Tatsumi, he is a first year in Ishiyama High, the school for delinquents. The story starts as he is telling the story of how he found the baby to his best (and only) friend Furuichi Takayuki. One day while fishing 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 the man splits in half revealing a baby boy. This boy is the son of the 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. The early chapters of the manga follow Oga as he attempts to 'pass on' Baby Beel to other students at Ishiyama, (The theory is that if Oga can find someone more evil and stronger than him, Baby Beel will attached to that person instead of Oga). After subsequently fighting and defeating all members of the Touhoushinki and in the process, destroying Ishiyama High itself, Oga and company are transferred to Saint Ishiyama Academy, which appears to be a direct opposite of the delinquent school.