Queensland miner, Oliver Woodward (Brendan Cowell), undertrained and never having faced hostile fire before, finds himself on the Western Front leading a secret team of Australian tunnellers fighting to defend a leaking, labyrinthine tunnel system packed with high explosives. If Woodward and his men can hold out, the massive mines will produce the biggest explosion the world has ever known and could change the course of the war. But the Germans have discovered the Australians’ underground activity and as zero hour approaches, the whole allied strategy could be in jeopardy...