When in 1998 Chilean judge Juan Guzmán was assigned the first criminal cases against the country's ex-dictator, General Augusto Pinochet, no one expected much. Guzmán had supported Pinochet's 1973 coup against the democratically elected president, Salvador Allende, and had worked as a judge during Pinochet's dictatorship. The filmmakers trace Guzmán descent into what he calls "the abyss," where he uncovers the past - including his own role in the tragedy.