Clan of the Nakagamis - The Devil Cometh

Haruka and Nakagami have been seeing each other for months now, and have decided to take their relationship to the next level. Unfortunately, Nakagami's power-tripping relatives disrupt the peace in their loving relationship. The two know that they can make their future together work, but what will happen to the relationship when a formidable demon appears from the Nakagami clan?