After , Artyom becomes disillusioned with the constant infighting and corruption within the Metro and leaves the Spartan Order. He soon becomes obsessed with proving that other human survivors exist outside of Moscow and makes numerous dangerous expeditions to the surface, much to Anna's concern and Miller's frustration. However, on one such expedition with Anna, they witness a working train running on the surface. Before they can follow it, they are captured by Hansa soldiers along with a couple of people who claim to be from outside of Moscow. The Hansa soldiers execute the other prisoners and Artyom is shot and left for dead. Surviving the gunshot, Artyom follows the soldiers to their base to rescue Anna, and in the process inadvertently destroys a signal that was blocking all communications going in and out of Moscow. Radio transmissions from all over the world begin to be picked up, and Artyom and Anna realise humanity has not gone extinct. They escape by stealing one of Hansa's trains, the "Aurora", with the aid of a defected Hansa train engineer called Yermak.
As the train leaves, the Spartan Order moves in to retake it and are shocked and confused at Artyom and Anna's presence. Knowing that Hansa will have all of them put to death for knowing the truth, Miller concludes that the Spartans' best chance of survival is to flee Moscow. Once outside the city, he reveals to the others that while many of Russia's cities were bombed, the war did not end and proceeded to occupy what was left of the nation. To prevent more bombs from being dropped on Moscow, the Russian leadership decided to secretly jam all communications to make the outside world believe nobody had survived. They then receive a radio broadcast from Moscow Defense Command calling for survivors to rally at the "Ark" located at and Miller decides to head there, believing that the Ark is where the Russian government has rebuilt itself.