Time Turner only wanted to cure baldness.
The Doctor wanted to find a way home.
The two know must live in each other's (horse) shoes, trying to find a way back to their world. But first, Some Thing Wants Them To Learn Something. And It won't let them return until they learn it.
Too bad neither of them have any clue what they need to learn.

Chrysalis, Tirek and Cozy Glow are free from their prison of stone! But now Cozy Glow is British and insist on being called The Doctor or Mr. Clever. Cozy Glow has also become Chrysalis's log and is now an odd looking changeling. Even worse, Cyberman have made Cyberponies. Daleks have arrived. And it's up to the greatest villains of Equestia to defeat the greatest villains from the stars. While running from the cops. Oh, and there's two Cozy Glows.