Yotsukuri Kageko was once a female detective who fought to uphold justice. However, when Shadow, a righteous demon warrior who has battled devil worshippers since ancient times, sought a successor, he recognized Kageko's pure sense of justice and chose her as his heir. Kageko thus transformed into a shadow-controlling demon warrior, her intense hatred for evil empowering her shadows. As a result, she splits into two beings, becoming the justice heroine "Shadow Girl." But after the split, Kageko's original body suffers a critical weakness—severely diminished combat strength. The evil organization Black Spider, aiming for Japan's conquest, plans to exploit the moment of her transformation, attacking her vulnerable original body to defeat Shadow Girl. Furthermore, the demon warrior Tokuda-Ne intends to corrupt both Kageko's original form and Shadow Girl, broadcasting their downfall nationwide… [BAD END]