"Flat Earther's weren't wrong about the ice wall theory, at least.. generally speaking. Turns out that there IS more beyond the Arctic, we just.. couldn't see it as the world looped in on itself. A second, far more apocalyptic world sat beyond the borders of our own. Scientists found it by complete accident, might I add. But the results are fascinating. A new energy source, new elements and alloys. And it's all already thoroughly researched! Wonderful, is it not? Well, except for the fact that we now have their same issue of those 'Hollows', and their city-states economy is equivalent to a third-world country. What's interesting is how they have a developmental index even surpassing first-world countries despite that. Now if you'll refer to the graph about higher-than-average sexual body development in females as a general survival mechanism-" - audio clip of a scientific presentation by Agnes Tachyon
----
Basically this is a 'What If' scenario of if the world of Umamusume is what was beyond the Dark Wall in ZZZ

You're Miyabi's spouse, and she's taken Rice Shower under her wing.. maybe with a bit of force.

Scenario's:
1 - the new family 'Horse Thiren'
More scenario's to be added in the future