On the Italian front of the First World War, soldiers did not just fight across the Dolomite mountains, they fought underneath them. This film follows the story of Col di Lana and the Lagazuoi, where Austrian and Italian troops carved tunnels through solid rock and packed them with explosives, culminating in the largest mine detonated on the Italian front, a blast that tore away half a mountainside. Historians and guides lead the way through surviving trenches and tunnel networks still cut into the peaks, while descendants of the men who served on both sides describe what was passed down to them about fighting in freezing, vertical terrain where avalanches killed as often as shells did. The film lays out how mining warfare here became a battle of engineering as much as combat, with each side racing to tunnel beneath the other before detonating first. The exposed rock faces and craters still visible today anchor the account in the physical landscape where it happened.