Seven years after being ripped apart, Hotaru and Isamu have reunited at last. The nine-tailed demon fox takes his human love and their daughter back to his castle in the yōkai world to live happily ever after... but can they? Isamu has a dark history that will shadow their new life together, and he doesn't want to talk about it. When an unexpected visitor drops by to claim an old favor, Isamu has no choice but to go on a quest to Hell or risk losing Hotaru forever! Meanwhile, Hotaru is on a quest to discover who her demon lover truly is and where he comes from before it's too late! Can Hotaru's love triumph over Isamu's past?