On a top-secret dive seven miles down into the Mariana Trench, deep-sea submersible pilot Jonas Taylor crosses paths with Carcharodon Megalodon, the 70-foot, 100,000-pound prehistoric cousin of the Great White shar. Discharged from the Navy, ridiculed by his peers. Jonas must prove to the world that the sharks still exist. When an opportunity to return to the trench presents itself Jonas takes it, intent on returning topside with a six-inch white tooth. But man's presence in this unexplored realm accidentally releases one of the creatures from its purgatory, and the hunt is on to capture it.