Some ponies think Diamond Dogs hoard gemstones for the same reasons ponies do. Others think they eat them, like dragons. If ponies knew the truth, they might not be so eager to rob them of their subterranean treasure. If only they knew.
Everypony has their secrets. Twilight never imagined those her own best friends might be hiding from her, until one of her new duties as a princess brought her stumbling headlong into a side of Equestria she never even knew existed.
Bit is the first of her kind, a crystal machine shaped like a pony. For lifetimes she served, until her master was long dead. Instead of fall dormant like the other machines, she snapped. Suddenly, she could choose. She did.
Tracy needed somewhere to stay, how was he supposed to know that it was in another universe? Now he'll somehow have to hold down a job on Earth while living as a pony in Equestria. It's either that, or say goodbye to being human.