18,000 feet below the surface of the Pacific Ocean is a motherlode of valuable manganese, but the only way to retrieve it is through a series of strategically placed nuclear detonations. It could trigger a massive earthquake along California's San Andreas Fault. In the eerie blackness of underwater mountains, famed marine engineer Dane Brande enters a high-tech killing duel with submarines and remote controlled, missile-laden robots. He's determined to prevent an apocalypse, but he may be too late.