The Vault has been opened. All around Equestria ponies are left to confront their strange new reality: that they weren’t the first to walk these lands; that they aren’t the first sentient species to have inhabited the planet.

Now, only a few years after becoming a princess, Twilight Sparkle and her friends are forced to navigate issues they couldn’t possibly have prepared for. It drives a wedge between some of them, where it weaves a common bond between others. It leads some on the path to growth, and others, down a seemingly bottomless well of desperation and violence.

And at the center of it all are the bones of the ancient creatures once forgotten to ponykind. They called themselves ‘humans’... and they’ve left quite a few things behind.