|Ryo Utsugi, a high school student, begins suffering nightmares. Ryo's sister, Saori, is kidnapped and used as a ritualistic sacrifice by a group of satanic cultist, who’s primary goal is revive Demon Lord Dante. Ryo's premonitions guide him to the ceremony and he saves her prior to the cultist's ceremony disrupted by militant Christianic followers of God. Believing that Ryo's new-found powers could ultimately awaken Dante, the most powerful of the demon lord, and beasts, the cultists cause a chain of events that lures Ryo high into the mountains, where he discovers a portal that takes him deep into the Himalayas into Dante's prison.
Dante uses Ryo’s telekinetic powers to free himself before eating him alive, as the cultists summon Dante to Japan. Ryo consciousness conquers Dante’s who rampages Nagoya with his new body, only to end when Dante encounters his old best friend Zenon.
Later Ryo encounters BeliZebub, the leader of the cultists, who tells him that his birth family was killed in a car accident and his father, who is both a doctor and a leader of a rival cult dedicated to God's will, was the one who saved him. He also meets the demon Medusa, who assumes the form of a supermodel named Saeko Kodai. Medusa later rescues Saroi from Lamia’s labyrinth and restore his memory. With His memory restored, Dante resolves to both joining and leading the cultists in there fight against God.