Akemi Nakajima is a high school student and a computer programming prodigy who created a program that can summon demons from Makai. His original intentions for the program were to gain revenge on a classmate who had fought with him. He brings his friend Yumiko Shirasagi, a transfer student that became interested in Nakajima and found to be the reincarnation of the goddess Izanami, to combat the malicious demons he unleashed. Nakajima had been tricked into summoning a demon named Loki with his program, whereas the American computer genius Isma Feed has summoned the demon Set in order to use its power. The game is assumed to take place after the first two Digital Devil Story novels when the demons Loki and Set have been defeated, and it diverges from the original ending of the third novel. The demon Lucifer has revived them, though, in order to prepare to invade the human world once again.