Of the many genocides that racked the world during the latter half of the 20th century, few carried the weight or wielded the horror of the Khmer Rouge massacres in Cambodia - wherein Communist dictator Pol Pot annihilated between 1.4 and 1.7 million countrymen, and subjected innumerable others to incarceration and torture. Beth Pielert's Out of the Poison Tree marks one of the very few documentaries to put a human face on these events by filtering the massacres through the prism of one family's experiences. At the center of Pielert's film stands Thida Buth Mam, a woman who can easily trace her father's disappearance to the hellish doings of the Khmer. As the documentary unfurls, she embarks on a long and frequently harrowing journey to attempt to understand exactly what happened to him. In the process, she comes face to face with victims, family members of victims and former torturers, living in a country still reluctant to discuss the horror that once permeated it.