Detective Sawamura Yuka tirelessly patrols the city to protect its peace. One day, she arrives at the scene where a civilian is being attacked by monsters. Pretending to call for help, she dons a mask and transforms into the Beautiful Holy Woman Masked Fontaine. Fontaine defeats the monsters and rescues the victim, but is suddenly ambushed by hidden monsters and ultimately defeated. Captured and taken to the demon clan's hideout, Fontaine is subjected to intense sexual torment by their leaders. Losing her sanity, filled with despair and hatred, Fontaine embraces her own desires and transforms into the warrior "Dirty Fontaine." She begins purifying the demon clan, turning humans into prey for her lustful cravings, walking a new path with a lewd and wicked smile. [BAD END]