This stories is redone and continued in: The Student of Sun and Shadow
King Sombra's attempt to reconquer the Crystal Empire may have been thwarted, and he himself cast back into the shadows, but it will take more that that to stop a being who endured a 1000 year of imprisonment in ice and darkness. Especially now that he has set his sights on a new conquest. Twilight Sparkle's effort to save the Crystal Empire may have gone unrecognized, but not by Sombra. She has earned his interest, and his admiration. The implications of which Twilight fails to appreciate. And will regret.
This story was inspired by the fan comic A Somber Meeting by Omny87