Mizuki, a college student, possesses a special ability to transform into a heroine with powers based on the drink she purchases from a vending machine. As a member of the Drink Sisters, she fights to stop a mad scientist who manufactures the evil drink "Dark Water" and seeks to brainwash humanity. Battling in various heroine forms, Mizuki confronts the embodiment of evil—Dark Water. The outcome of her struggle drastically changes depending on the choices she makes. Can Mizuki truly save the people?... [BAD END]