For the first time ever the Royal Australian Navy has provided exclusive access to the Navy's most intense training program for its Clearance Diver Branch ? an elite unit at the frontline of national security. Over the course of nine months, it will take twenty seven young men to the limits of their mental and physical endurance. Only the toughest will make it. As soon as the candidates put on their numbered vests, their ordeal begins. Marathon runs, gruelling weight sessions, late night swims across Sydney Harbour, relentless diving drills and hours of marching through steep bush. They'll eat on the run, be deprived of sleep, and pushed beyond what they thought was possible.