Snowpiercer is based on the French graphic novel Le Transperceneige by Jacques Lob, Benjamin Legrand and Jean-Marc Rochette. It follows a group of survivors of an Ice catastrophe that live on a train that travels around the globe and never stops. The train is split into two groups: the rich and the poor. The poor people (including Chris' character, Curtis) are planning to revolt and overthrow the rich people. It's a pretty violent movie.