Inuyashiki Ichiro is an elderly, friendless man with an uncaring family.
However, a teenager who was with him at the time of the explosion, Shishigami Hiro, had the same fate as Ichiro, but unlike Inuyashiki, Shishigami becomes a sociopath who uses his new found abilities to murder classmates he dislikes and innocent people, including young children, just for amusement.