Vietnam is over-run with ghosts. To pass onto the next world, you need to die well - in old age, body unblemished, the proper rituals observed. But few of the five million people killed in the Vietnam War were granted such a peaceful ending. They became 'wandering souls' - doomed to eke out an impoverished existence on the edge of the everyday world.
In this two-part series, Cathy FitzGerald travels to Vietnam to hear how survivors of the War - both Vietnamese and American - co-exist with their 'invisible neighbours', the dead.
More than 300,000 Vietnamese people are classified as Missing in Action, nearly four decades after what's known in Vietnam as the American War.
Their families still search for remains.
Without a body and a proper burial, neither the dead nor the living can find peace.
Worse, the ghosts are angry. Condemned to wander, they watch as those who survive them reap the benefits of economic reform.
How can they make their voices heard?