In a world where humans and supernatural beings coexist, Adam, a creature created by scientist Victor Frankenstein, finds himself trapped in a millennia-long battle between two factions of demons. After the death of his creator, Adam lives in solitude and distrust, always aware of his nature. However, his life takes an unexpected turn when he is captured by a group of demons seeking to use his power to create an army of monsters.
Amidst this chaos, Adam becomes the target of a war he never asked for, leading him to the City of Darkness. There, he crosses paths with a woman named Terra, who is investigating the mysterious legacy of her late father, an expert in the occult. Terra discovers that the secret to immortality and the salvation of humanity may be linked to Adam. As both try to uncover the truth, Adam confronts his own identity, struggling between his desire for redemption and the instinct to survive.
The situation escalates when the demon leader, Naberius, sets his sights on Adam, seeking to use him as the ultimate weapon in his chilling plan. Thus, Adam must decide whether to join the humans and fight for everyone's salvation or embrace his nature and become the monster others expect him to be. With thrilling action and moral dilemmas, the battle for humanity and redemption is about to begin.