Among the 2 million Cambodians who died in the genocide of the 1970s were many intellectuals and artists, including musicians. The pop and rock music scene in the capital, Phnom Penh, had been flourishing until then. The music was inspired by Western rock and soul, but had a distinctly Eastern sound. After the Khmer Rouge took over, they destroyed it. We hear from a filmmaker who set out to piece Cambodia’s pop music history back together.