Down the less-traveled hallways of the Canterlot Castle, Twilight finds a staircase downwards into darkness. Behind metal doors and haloed in yellow sodium lights are three strange figures that haven't been seen in Equestria in centuries.

They bring with them many guarded secrets of Celestia's past as Princess, and what Twilight doesn't know might hurt her.

Based off of Steam Powered Giraffe lore.