1,000 years ago, the two sisters Celestia and Luna became corrupted. They merged together in one moment of goodness, and were banished by the Elements of Harmony. Princess Cadance is the ruler of Equestria, and she has her own faithful student- Lyra Heartstrings. Together- with the help of Roseluck, Amethyst Star, Sassaflash, Blossomforth and Octavia- she must save Equestria from the clutches of Nightmare Corona.