The Vietnam War, it will be no news to anyone, has had considerable impact on world history, both as a national tragedy for Vietnam and in its global cultural impacts. It sparked a mass movement of people around and out of Vietnam and the rest of Indochina. The song I’ve posted above is apparently about this migration. I couldn’t find any English translation of the lyrics and sadly do not know any useful Vietnamese. The Sympathiser follows the story of a migrant, the Captain, who journeys to the US as a refugee and sleeper agent for the Viet Cong.