Episode Title:
Shadow Play Part 2.
Episode Description:
The Pony of Shadows retreats to the darkest corners of Equestria to recover his lost strength after his thousand-year captivity. Rebuked by Star Swirl for unleashing Equestria's greatest threat, Twilight resolves to redeem herself by helping him and the other Pillars return the Pony of Shadows to limbo, this time by sacrificing the Elements of Harmony in the heroes' place. The Cutie Map directs the ponies to the monster's location, and Starlight learns from the Pillars that the Pony of Shadows was once their friend named Stygian, whom they cast out for attempting to steal their artifacts. When the ponies use the Elements on the Pony of Shadows, Twilight and Starlight see Stygian and reach out to him, learning that his supposed betrayal was actually an attempt to help the Pillars protect Equestria. The Pillars realize their error and help the six friends use the Elements to separate Stygian from the shadow entity, which is re-imprisoned. Star Swirl apologizes for the all trouble he caused with his pride. With their friendship restored, Stygian and the Pillars remain in the present era to explore Equestria.
