Two vaults with two experiments. One set the ponies out on their own, forming a tribal group. One kept them close, creating a vault-dweller herd of ponies. But there's still one more to be seen. How were they treated and what did they form?
Let's bring this story to a close(?) with the ongoing adventures of our mane character, Buttercup, the robotic companion horse designed to serve at a child's side, even in the wasteland.