Seoul Train

Seoul Train is a 2004 documentary film that deals with the dangerous journeys of North Korean refugees as they escape through China to find refuge. These journeys are both dangerous and daring since, if caught, they face forced repatriation, torture, and possible execution. The North Koreans are aided by a loose band of activists who have formed an "underground railroad" of safe houses and escape routes to evade the authorities and North Korean agents.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.

Poster © the film's rights holders.