Slate has been on his own since a foal. As a member of the forgotten race of 'deep earth' ponies existing far in Equestria's under ground, he feels the earth's call inside him, leading him by instinct to where he needs to be so the rock can be shaped. Slate finds himself called ever upward toward the pony who unknowingly changed the course of his life, and when he reaches the surface his life will be forever changed by the wonders and ponies that he finds.