Everything is going pretty well at Canterlot High. Sunset Shimmer has changed her ways, Trixie is acting slightly less arrogant, and the quiet kid, Zecora, is finally making some friends. But when a new teacher, Professor Lancie, mysteriously joins the school staff with almost no explanation, some students began to get suspicious. It soon becomes clear that this mystery is much more dangerous than it appears. And it doesn't make much sense, either.

But then again, what's the fun in making sense?