Humans.

Truth or myth? Ancient lost civilization or just an old pony's tale?

No pony has ever seen one, and most haven't even heard of them. But Lyra knows that these wonderful creatures are more than just old legends, and she's going to find out... and possibly drive her roommate insane in the process.

Twilight Sparkle is summoned to settle a legal matter involving The Great and Powerful Trixie... What in Equestria did she do now?