More than seven years after the world has become a frozen wasteland, the remnants of humanity inhabit a gigantic, perpetually-moving train that circles the globe as class warfare, social injustice and the politics of survival play out.
Nima heads for Snowpiercer; Layton and the Tailies fight their way uptrain when Ruth is captured; Nima tries to cut a deal and runs to the rocket control room to initiate the launch sequence.