High school girl Kokoshita Kokoro wields the power of the Aurora Heart, granted by an angel, to battle demons. One day, while discussing their future with her classmate Yasukura Inochi at school, the demon lord Dande suddenly appears with his minions. To protect Inochi, Kokoro tries to flee the scene, but the two are eventually cornered with no escape. Kokoro approaches Inochi and punches her in the gut, knocking her unconscious. In that moment, she whispers, "Inochi, I'll protect you," and transforms into Aurora Heart. Inochi secretly witnesses the transformation and smiles faintly, puzzled. Aurora Heart boldly declares her name before the enemies and swiftly defeats Dande's underlings one by one. As she chases the fleeing Dande and his forces, she corners them and prepares to unleash her ultimate move, the Aurora Flash—but suddenly, the super-strong monster Goura slams into her, smashing her into the ground. Caught off guard, Aurora Heart desperately struggles to get back up... [BAD END]