Summer vacation has arrived in the human world and Sunset Shimmer takes a trip back to Equestria. However she comes back to something more than she bargained for.
As kids, Twilight and Sunset were best friends, but a tragic accident cut their friendship short. Years later, Twilight investigates the incidents at Canterlot High and comes face to face with what appears to be a literal ghost from her past.
After being abandoned by her friends, Sunset Shimmer wanders the steets alone, with no hope left, she gives up, only to be saved at the last second. Meanwhile her friends are trying to find her, and apologize for what they've done.