When she discovers an asylum of insane ponies, Twilight Sparkle vows to find a cure. Five years later, her mother ends up in an accident, making her mentally disabled. Becoming desperate, Twilight tests her newly-fused potion on herself. However, the experiment goes horribly wrong, unleashing her murderous, darker side, which calls itself, "Nightfall Hyde". Soon, the lives of many are placed in grave danger, and Twilight must find a way to subdue the creature. But at what cost?
I do not own My Little Pony or Jekyll and Hyde the musical. This fanfiction is simply based upon the musical.