Lock Light, the Second Son of King Sombra, Heir to the Crystal Empire, is locked in the Demon Pit of Karakhum, the place where all the creatures who have, had, and ever will attack Equestria and Ponyville are spawned. Twilight Sparkle, Rarity, Pinkie Pie, Spike, Applejack, Fluttershy, Rainbow Dash, and the Doctor must help Lock Light confront his surrogate brother and First Born Son of Sombra White Lightning with his powerful and evil dark magic in the pit. The result is the a duel of magic between them which nearly destroys the Crystal Castle. Who will triumph? Lock Light the Second Son of Sombra? Or the First Born?