A unicorn named Althaia comes to Ponyville and tells the mane six that a great darkness is coming to shroud the world in an eternal darkness. However, they don't believe her until they begin to have strange dreams a giant snake with wings destroying Equestria in the night.

Althaia then tells them that the only way to stop the villain is to awaken a deity said to be the creator of the sun which lies in the heart of Equestria. Now, they must go on a perilous journey to save the world and the elements of harmony might not be able to save them.