Humans have undergone genetic mutations, where those with superior genes may acquire superhuman abilities, while those with monster genes may transform into monsters. The male lead, who has turned into a monster, regains his senses and is reborn through the female lead's sacrifice. This time around, he is a reformed playboy who protects the female lead, hiding among the superhumans. Covertly, he uses his monstrous form to hunt down other monsters and seize the ancient demonic god's power, in order to prevent its resurrection.