In the mirror universe of Equestria, King Sombra rules as a wise and good monarch, with one great secret. He loves the Princess Celestia, one from a different universe, as kind as his world's is cruel. He has loved her patiently for over a thousand years, and would continue to do so, if the cruel Celestia had not begun slowly to destroy his kingdom and his ponies.

She has offered him an almost irresistible temptation: to give her the key to that other universe, and to have his princess in exchange. He has always refused, but now his most trusted advisors beg him to accept. Can he oppose their temptation as well?

Based on the Reflections Arc of the IDW comic series, 17-20; set just before and just after the action of the arc, and just after Equestria Girls and before Season Four of FiM. Spoilers for the arc apply.