Over 1,300 American pilots were declared missing in action as a result of the Vietnam War. Nearly 40 years on, a special unit of the American military (JPAC) revisits the site where the fighter jet of Major Herman Knapp and his co-pilot Lt David Austin was shot down while returning from a bombing raid over Hanoi. With only 30 days allowed to excavate the site, can JPAC find the servicemen's remains and close the case? 5/6.