When an aerial pursuit with Dr. Eggman goes horribly wrong, Sonic the Hedgehog and Miles "Tails" Prower find themselves in the magical land of Equestria. As they learn that their entrance into this world has shattered an ancient power known as the Harmony Crystals, the land's greatest villains rise to seek revenge. Now it's up to Sonic and his new friends to restore the crystals and save Equestria from disaster.