Iris and Ruby go to look for their unicorn Heartsong after she went to the Fairy Forest to have her foal but never came back.

When someone discovers Rainbow Mist and wants to use her magic, Iris and Ruby must protect the unicorn magic before it is gone forever.

A human girl named Iris, who protects the unicorns in the Enchanted Forest from the outside world, does not want to be like Lyric, the misfit of the unicorn herd, so maybe she should just dance in the school talent show with her friends instead doing what she really wants to do--magic tricks.

Can Iris help the other unicorns welcome Ember Shadow into the herd, even though he has the marks of a dragon, which the unicorns do not want to accept?

Iris would usually love to go visit the unicorns with her younger sister Ruby. But with a big school report due the next day, Iris has to focus. She doesn't have time to visit the unicorns. And she is not in the mood to listen to Ruby's problems. But when Ruby goes missing, Iris worries she's made a big mistake. With the help of stallions Ember Shadow and Tempest, Iris searches the Enchanted Realm for Ruby. Can she find her sister and make things...