After the events of Rise of the Tomb Raider a gas cloud was forming over an old Soviet Weapons Research Facility, and would reach the Remnants base within a day. Nadia managed to find records of this place, and learned of an old experiment to create super-soldiers, the experiment failed however, and was shut down. Under Konstantin's orders, a group of Trinity soldiers reactivated the factory. The factory produced a gas which transformed the Trinity soldiers into primitive bloodthirsty savages, like the prisoners Soviets experimented before. Sofia, who has learned how to fly a helicopter, brought Lara to the factory, and circles over it, while Nadia read Lara instructions on how to shut down the factory permanently. Lara managed to destroy the research facility, and with the facility's explosion, burn out the gas that was already formed over it.
There are several rewards that can be used in the main game by freeing 8 prisoners.
- Voidhammer Shotgun: A Sawn of Double-Barrelled Shotgun with a short range but massive damage.
- Ushanka Camo Outfit: A soviet camouflage jacket, and hat.