A group of survivors searching for food witnesses the crash of a Russian military helicopter and move in to save anyone who survived. When they reach the crash site, they only found one survivor, a female Russian Army officer, and fight off a massive swarm that attempts to overrun the crash site. 

After fending off the zombies, the officer enlists the groups' help in activating a deadly nerve agent throughout Moscow that is lethal to both humans and zombies. The plan is to evacuate any survivors still alive in the city and kill all of the zombies in Moscow, but the nerve agent will leave Moscow uninhabitable for six months. 

After sending out a signal to warn all survivors to evacuate before the nerve agent is released, the group infiltrates a secret facility where the nerve agent can be released. They successfully release it throughout Moscow, killing all of the zombies in the city. 

Five days after being stranded in the bunker, the group believes they have been abandoned, but re-establish a connection with the officer who tells them to gas the tunnels to kill off the zombies hiding inside. Soon after, the Russian Army arrives and evacuates the group from the station as it is being attacked by multiple zombie hordes.