The arrival of humans from Terra will spark many changes across the political, moral, and ethical landscape of Equus for ages to come, or will it? Will Equestria be able to cope with the changing landscape or are the "Sins of the Father" inescapable.

Are things in Equestria as black and white as the ponies think they are? How will Terran soldiers with deep-seeded PTSD, and emotional and physical scars of a war for survival cope with a planet where the inhabitants espouse love and tolerance yet have very volatile skeletons in their closet? And why are humans already on this planet?

The blog post HERE explains more.

UPDATE:
Added Mature tag because language is going to get heavy.