While on vacation, Twilight Sparkle finds King Sombra regenerating in the dungeons. She attempts to reform the former tyrant with permission from Celestia, while also learning dark magic to do for good. Unbeknownst, the more the two of them are near each other, she begins to change. Growing a more dark and cold personality, she might end up embracing her dark side. And how does Starlight Glimmer have a part in all this?

Gore tag just to be safe.