In Equestria's history, it has been Princess Celestia and Princess Luna, along with, most recently, the royal couple and the Element bearers. Because of them, peace rules over the world. But one day, five years after Luna's return and Nightmare's second defeat, a new evil arises, one that has existed under the royal nose for years, one that wishes to take the world for itself. In the most vital decision to be in her career, next to banishing her sister, Celestia has done something she hoped she would never have to: fight the darkness, with the darkness. Her call rang out across the world, and those chosen answered. This is the story of the Shadow Guard, Celestia's personal peacekeepers, and how they, not the usual heroes, saved the world.