The Last Thing Lost examines the remarkable life of Sarith Ou. His narrow escape from the Khmer Rouge genocide in the 1970s took him on an improbable journey to small-town Wisconsin. Sarith remained connected to his culture, leading Cambodian communities in America, but his past still haunted him. With the help of his friend Roger, a Vietnam vet turned psychologist, Sarith returns to Cambodia with renewed purpose more than two decades after his departure.  Together, Sarith and Roger bring hope to rural Cambodia, while healing their own decades-old wounds.