Haruka, an employee at a real estate company, is wallowing in self-pity about her work blunders and unrequited love for a now-married colleague when an unexpected "meteor" crashes through her window. The culprit? A strange man who claims to be the demon king. He shocks her further by revealing that she was a saint in a previous life, making them archenemies.
Haruka can hardly believe this absurd scenario lifted from a light novel. The demon king boldly declares that he will make her happy and then send her spiraling into despair once again.
Thus begins the story of a former saint turned corporate slave living with a demon king who becomes an affectionate suitor.
