On the eve of the long-awaited Khmer Rouge trial, an American survivor of the genocide returns to Cambodia hoping to unlock the mystery of her father's disappearance in 1975. Thida Buth Mam's quest intersects with many silent voices: widows, survivors from remote villages, monks and even former perpetrators. Her search for the truth stirs up the fractured pieces of one family's nightmare, unearths an unimaginable heartbreak and ultimately shines light on a people's broken silence.