People possessed by demons are robbed of their luck and are more likely to die from an unfortunate accident. One such individual is Yoshinaga Yukihiko who simply wants a peaceful life surrounded by friends and a girlfriend, but due to the spectral presence constantly following him, everybody he tries to get close to suffers the same misfortune he experiences.
While returning home from school one day, a giant demon unexpectedly emerges, intent on taking Yoshinaga’s life. Fleeing the scene, he takes refuge in a church where he encounters a beautiful nun named Alicia Baal who, aware of the situation, makes a pact with Yoshinaga to exterminate the demon. However, what are Alicia’s true intentions in forming a contract with Yoshinaga?