The ponies of Equestria prepare for their first Friendship Festival, overseen by Princess Twilight Sparkle in Canterlot. The festivities are interrupted by an invasion of monsters commanded by the broken-horned unicorn Tempest Shadow, who uses magical orbs to petrify Twilight's fellow princesses. Princess Celestia gives Princess Luna incomplete instructions to seek help from "the queen of the hippo" before they are both petrified. Twilight flees the city alongside her five pony friends – Pinkie Pie, Rainbow Dash, Rarity, Applejack, and Fluttershy – and her assistant dragon Spike, and the group begins their search for the "hippos". Tempest pursues Twilight under the orders of her superior, the Storm King, who requires the magic of all four princesses to empower his mystical Staff of Sacanas, and promises in exchange to restore Tempest's horn.
