The River of Wrath.

Set in North Korea, one of the most secretive and oppressive countries in the world- Gi-cheol's family is overjoyed when he gets a job as a customs officer at a checkpoint near the border. He was by-the-books man who never took bribes from the smugglers and was loyal to their great leader, determined to weed out any traitors who were against the regime. But one day, when one of the smugglers sets him up for bribery, Gi-cheol and his family have no choice but to escape the country and cross the border… whilst the very comrades he trusted turn their gun barrels at him.