Winter used to be the personal student of princess Luna before she was banished to the moon. Unfortunately, his disagreement with this decision caused Celestia to banish him as well; he was put to sleep until she determined he wake up.
That time is now, Luna has redeemed herself and Celestia can no longer detain Winter in good conscience.
However, Winter has had no time to his own thoughts for a thousand years, or a cleansing rainbow of harmony to set him back on the right path. Luna has tried her best to get him to change his thinking, but to no avail. Now Winter must learn about new Equestria and friendship from the best: Twilight Sparkle.
But not everything is as easy as cutting apple pie. Twilight and Winter do not get along in the slightest, eventually at a group outing their rivalry comes to a head and throws them into a world neither of them were prepared for. On their own, they now must learn to work together to return to Equestria.