After losing her parents, Mio's dream of becoming a pianist was all but taken from her. Now, she works as a house keeper at Arc en Ciel, a luxury hotel in the heart of the city. One day, a flurry of expected events introduces Mio to Taisei, the heir to Arc en Ciel. The next thing she knows, she is accompanying him to the hotel's anniversary party -- as his lover! The task? To put an end to his arranged engagement! On top of that, Mio has to continue to pretend to be Taisei's fiance even after the party is over...?!