Ruby's new classmate, Cole, has a mysterious key. It looks a lot like Ruby's key to the Magic Gate. Could Cole be a Unicorn Guardian too? But there are bigger problems in the Enchanted Realm. Starsong was stolen by dragons and taken to the Fire Mountains. And when the moon is full, the dragons will feast. Can Ruby and Iris rescue Starsong before it's too late? There are unicorns behind Magic Moon Stable, but no one except Iris and Ruby know they exist. As Unicorn Guardians, it is their job to protect the unicorns and their magic to keep them safe from the outside world.