The Equestrian Civil War begun in Armor's Game continues as the Princesses prepare to move against the usurper Blueblood in Canterlot, while Princess Cadance leads an expedition north to find a nameless terror

Thirsty for vengeance against Queen Chrysalis, Shining Armor leads an army south to deal with the Changelings. Prince Blueblood schemes for absolute power in Canterlot. And in the black north of Equestria, an ancient terror threatens to destroy all.