Ruby loves riding fast on Tempest. Iris enjoys showing off her control and skill with Lyric. But who is the better unicorn rider? Their friend Cole suggests they have a race. Whoever can cross the Diamond Desert and reach the magical Lotus Gem first is the winner. But the Diamond Desert is filled with dangers. Can Ruby and Iris overcome their rivalry and work together to make it back home? There are unicorns behind Magic Moon Stable, but no one except Iris and Ruby knows they exist. As Unicorn Guardians, it is their job to protect the unicorns and their magic to keep them safe from the outside world.