The history of the town of Manehatten revolves heavily around the rock farm and its history. The caves, mines, and other gray features of the dry plains have been a part of Equestrian history for as long as the town itself has. So naturally when the twins Inky and Blinky find an ancient looking map carved into a stone tablet, the odds are against them finding any sort of treasure not already uncovered.
But hey, who knows? They might get lucky...
(There is no character tag for the Pie twins because none seems to exist.)