Unicorns to the rescue

"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 right before it's too late?"--Amazon.