It is said that the longer one's punctuality streak is, the better a boyfriend they will have. In accordance with this, Airi Hoshina strictly follows her routine in preparation for her dream life: to have a loving, wholesome husband and family. However, Airi's life takes a fantastical turn when a young boy appears from her hand mirror.

Named Aram Astale Ei Daemonia Eucalystia, the young prince of Astale is fleeing his kingdom to evade a magical spell. Unknowingly, his portal leads directly to Airi's hand mirror. Though he avoided the brunt of the spell, his escape did not completely save him from the magic's effects: a spell that was originally supposed to turn Aram into an old man instead ages his body to that of a 17-year-old whenever it is dark. Now, the only way to turn him back is a kiss from his beloved maiden. Busy trying to find her one true love, Airi wants nothing to do with it, but Aram insists his soulmate must be her!