On 28 February 2009 Kaing Guek Eav, alias Duch, appeared in the ECCC courtroom and made a two-hour speech where he asked for forgiveness for the appalling torture and execution of at least 13,000 prisoners at Tuol Sleng and probably more in the security camps of M-13 and M-99. Until this date, with the exception of a handful of judges, lawyers and a priest, he had not been seen or heard of for the last thirty years. How did a man, known to be kind and generous to fellow students, possibly transform himself into Comrade Duch, the Khmer Rouge's infamous executioner? This documentary revisits and searches for clues.