Following a failed attempt to halt global warming that sparked a new ice age in 2014, the last humans on Earth circumnavigate the globe aboard the Snowpiercer train. 17 years on, with the train rigidly divided by class, the poor inhabitants of the train's tail section, led by Curtis (Chris Evans), decide to rebel and demand better treatment and living conditions.

After freeing security expert Namgoong (Song Kang-ho) and his daughter Yona (Ko Asung), the band of rebels make their way to the front of the train in search of its creator, Wilford (Ed Harris).