During summer break, childhood friends Naoto and Rika finally confess their feelings and begin dating, only for their newfound happiness to be disrupted by the sudden arrival of the devil Asmodeus. When Naoto proves powerless against the intruder, the angel Luvriel intervenes to protect them, though she is left weakened by the battle. Revealing an ancient conflict between heaven and hell, Luvriel asks Rika to take up the fight in her place as the celestial warrior Djibril. At the same time, a jealous classmate named Meimi falls under Asmodeus's influence and is transformed into the dark heroine Misty, setting the stage for an impending confrontation.