"Snowpiercer" is a science fiction television series based on the 2013 film of the same name. The series is set in a post-apocalyptic world where an experiment to stop global warming resulted in an eternal winter, and the only remaining humans live on a train called Snowpiercer, which perpetually circles a frozen post-apocalyptic world.
A significant feature of "Snowpiercer" is its exploration of social hierarchy and class struggle. The train is divided into cars, each with its own social class. The wealthy and powerful live in luxury at the front of the train, while the lower classes are confined to the tail cars. Season 4 likely continues this theme, possibly introducing new conflicts or resolutions related to these social dynamics. snowpiercer s04e01 dvdrip