When the Ponyville History Museum puts a strange and mysterious artifact on display, Sunset Shimmer starts acting strangely. And so, it looks like Twilight's the only one who can stop her ... or will she help her instead?

More in my Equestria-Girls continuity! (But again, not intricately tied to the other stories, so it works as a standalone). Set vaguely before the Camp Everfree movie, but after Friendship Games.