Seismologist Jack and his fiancée Karen go on vacation to a lakeside town, but unexpectedly discover a charred corpse and what seems to be the remains of an exploded yacht. It turns out that not far away, due to a mining oversight, they accidentally dug up a lithium vein buried deep underground. Lithium will immediately ignite when it comes into contact with water, and this vein is actually buried under the lake! Deadly gases are spewing out from all over the town's underground areas, igniting indestructible flames. As the military orders the area to be sealed off, two scientists who rush in to help—also Jack's good friends—are trapped in the lithium mine due to an explosion-triggered earthquake! Jack ventures deep underground for rescue; he must stop this catastrophe before the explosion, saving the lives of the villagers.