The natural beauty of Hawaii is dominated by the mighty bulk of Mauna Kai - the world's largest volcanic mountain, dormant now for seventeen years. But thrity miles beneath the surface, white hot molten rock is beginning to surge upwards. Driven by a limitless force below, the fiery magma rips open new channels and continues it's relentless advance toward the world of man. The first victims - a father and his two young sons camping on the mountain-side. Suddenly the ground yawns open and all the fury of hell erupts...