Stream The Fall of Saigon Online Free – Watch Full Movie from Home at 123Movies. . In April 1975 -- despite a ceasefire agreement -- the North Vietnamese communists took Saigon and the world by surprise, mounting an offensive that ousted the South Vietnamese government. This enlightening documentary recounts the last two years of America's military engagement in the country and the U.S. role in Saigon's fall. Interviews with former National Security Adviser Henry Kissinger and North Vietnamese officers provide context.