Master diver Frank McGuire (Richard Roxburgh) has explored the South Pacific’s Esa-ala Caves for months. But when his exit is cut off in a flash flood, Frank’s team—including 17-year-old son Josh (Rhys Wakefield) and financier Carl Hurley (Ioan Gruffudd)—are forced to radically alter plans. With dwindling supplies, the crew must navigate an underwater labyrinth to make it out. Soon, they are confronted with the unavoidable question: Can they survive, or will they be trapped forever?