During the First World War, thousands of Aussie diggers and other Allied troops passed through the French town of Vignacourt, two hours north of Paris. Many had their photographs taken by Louis and Antoinette Thuillier as souvenirs while they enjoyed a brief respite from the carnage of the Western Front. For all too many, this was their last moment away from the lines before being sent to their deaths in battles that are now part of the mythology of Australian nationhood - Pozieres, Bullecourt, the Somme. The weariness and horror of battle is reflected in their eyes, but the photos also capture a sense of camaraderie, high spirits and even a soupcon of romance. The Lost Diggers is the riveting detective story of the hunt across northern France for a rumoured treasure trove of antique glass photographic plates that led investigative journalist Ross Coulthart to an ancient metal chest in a dusty attic in a small farmhouse.