Kita-Tsubame, the only city in Japan where polygamy (a.k.a. Harem Marriage) is legalized, is hosting a Harem Marrython! Ryu has his eye on a new bride by the name of Misuzu, a single mother who wins over Koharu with her genuine smile and love for her daughter... But behind that smile lies a dangerous past. Now, the Date family must race to determine whether their bride-to-be is a sinner or a saint!