Many North Koreans are desperate to escape their homeland, willing to risk their lives to get out. A movement of activists is trying to help, but the mission is dangerous. If caught fleeing or assisting others leave, the punishment is possible torture and execution.
Anderson Cooper talks to Jim Butterworth about his film "Seoul Train," which documents the perilous journey for four adults and a toddler who escape into neighboring China. It's a rare look inside the lives of ordinary North Koreans seeking freedom.
Butterworth's sources tell him that agents from North Korea infiltrate China to go after defectors and the activists in the underground railroad.
"China does not want the North Korean regime to collapse. That would mean unification, but before that occurred, you would have millions of desperate hungry refugees streaming across the North Korean border into China, upsetting a region that's already politically unstable to some extent inside China," he says.
Watch the interview to see a clip from "Seoul Train" and learn more about the dire conditions in North Korea.