Crystal Princess Mi Amore Cadenza and Prince Shining Armor have two un-identical twin daughters, Angel Heart and Starry Night. One fateful day, a mysterious pony presents an unknowing Princess Celestia with a magical amulet. It turned the Sun Princess suddenly evil, and under the influence of the amulet, she turns on Starry Night. Angel Heart worries about her. Is her sister strong enough to face the upcoming ordeal? Or is she doomed for a heartbreaking future? Either way, Angel Heart must help her sister to cure Princess Celestia before it's too late.