A Unicorn unwittingly unleashes the ancient spirit of Shadow, turning Equestria into a gray wasteland. The Elements of Harmony team up with Princesses Celestia to stop the evil Shadow from freeing her sister, Silence, from the lowest level of Tartartus while tackling diabolical powers from the dawn of Equestria that were imprisoned within. Together they learn about how Equestria was made and just how powerful their bonds of friendship really are. OC Villains and a few minor OC ponies.