Old World Blues is the third major add-on for Fallout: New Vegas, focusing on the Courier being transported to Big MT, a pre war science and research facility. There the Courier discovers their organs have been removed by a group of pre-war scientists and held as leverage in order to make the Courier do their bidding. The player will explore Big MT and acquire all manner of technologies and items in order to combat the mysterious Dr. Mobius and ultimately, get their brain back.