The changelings, years after the invasion of Canterlot, struck at Equestria once more, this time with a highly industrialised army - panzers crashed through Equestrian troops, technologically inferior, taking Acornage in very few days, pushing to Vanhoover and even as far as Tall Tale.
Celestia erupted in fury.
The Solar Empire drove the changelings back, led by Empress Daybreaker, and within a year the changelings lands were Equestrian territory. Not all ponies accepted the new tyranny of Daybreaker, who considered herself a Goddess and the ponies her 'children' of sorts, especially the thestrals, whom had earlier enjoyed much better rights only to have those rights rescinded and finding themselves targeted.
Major General Sharpened Sword was one such figure, an earth pony stallion and hero of the war. It's up to him to rescue Equestria - can he help the resistance, lead a revolt, and rescue Celestia from the grips of her alter-ego, or will he stumble, failing to manage the high-exposure of being a hero and the favour of Daybreaker combined with his own beliefs in harmony and the old Equestria?