An old film reel is uncovered. Shot by a Japanese news agency, it shows a village in North Vietnam sending its young men off to war. Who are they? What were they thinking as they left for the battlefield? The undocumented footage offers no clues - except a possible timeframe: It was taken sometime around 1971. 40 years after the end of the Vietnam War, our Asia Insight crew set out to find the young men in the film.