Peach Cream, a unicorn with an annoying little unicorn sister named Almond Velvet, is visiting Vastopia to meet her long-time-no-see friend, Sponge Spice. However, unexpectedly, something strange happens that cannot be explained, and Spice vaporizes into the air, to an unknown place. Peach is about to set off to find her, but Princess Twilight has a task for her first...