Rukia accidentally ends up in another world and loses her memories. She doesn't remember that she's a Soul Reaper and thinks she's human.
In this version, Rihan never met Yamabuki Otome. But Rukia is still a ghost, isn't she? Or does a Soul Reaper not count as a ghost? So do Soul Reapers fall within the scope of Hagoromo Gitsune's curse or not? Rihan never thought about any of this, though, because he thought Rukia was human.
Having been raised by the Kuchiki family, Rukia appears gentle and mild-mannered, just the type Rihan likes.
But in reality, Rukia isn't like that at all. So what?
Rihan says: I've already fallen for her, so what else can I do? I'll make it work. And not only will I make it work, I'll spoil my wife rotten.
Theme: What would happen afterward if the second generation survived?