Starlight goes back in time to stop Ponyville from being destroyed in a disaster. Twilight, having none of that, tries to reverse her meddling, only to realize Starlight may have been on to something.
Rainbow Dash wakes up one winter morning to find she's been turned into a young filly. With a counter-spell farther down the line than she would like, Rainbow must learn to deal with her less-than-cool situation and save what's left of her reputation