Outside a small village in France, on the night of July 19, 1916, 5,533 Australian soldiers were killed, wounded, or disappeared into the abyss of the Western Front. They suffered more casualties in one night that in the Boer, Korean and Vietnam wars combined. Through sheer determination, 250 of these fallen, mostly Australian, were unearthed from five mass grave burial pits. These fallen are now being identified through DNA processing and stubborn detective work. This is the exclusive, behind-the-scenes story of the largest excavation of World War One dead in modern times.