As part of the genocide enacted on the Cambodian people by Pol Pot in the 1970s, guards at the infamous detention centre S21 (code name for Tuol Sleng) interrogated and executed over 17,000 “threats to the state”. Survivor Panh, whose ability to paint saved his life, invites two survivors to meet with four guards at S21. Attempting to explain and understand the past, they wade through the vast records and photos left behind, gently interrogating the guards on their conduct and routines, which they re-enact with disturbingly repetitive and dead-pan precision. Drawing a fascinating, effective, yet disturbing picture, these scarred survivors from both sides, try to seek relief by describing a culture of paranoia and force that was designed to crush any trace of humanity.