When she falls down the stairs and gets tangled up with a pick-up artist, she is rescued by a man. However, the man was a yakuza looking guy...? She tries to avoid getting involved, thanks him for his help, and quickly runs away, but he takes her to a luxury apartment. He claims to be her fiancé, Kenjiro Kitamiya! Although she has no recollection of the incident, the marriage certificate in her own handwriting and her personal belongings in the apartment tell her that Kitamiya's claim is true. The shock of falling down the stairs revealed that she had lost her memory of the past five years, and had forgotten all about her fiancé Kitamiya...! If she has forgotten, all she can do is make him fall in love with her all over again.