After escaping an attack by what he claims was a 70-foot shark, Jonas Taylor must confront his fears to save those trapped in a sunken submersible.

A deep-sea submersible filled with an international research crew lies disabled at the bottom of the Pacific after having been attacked by a massive shark previously thought to be extinct. With time running out, expert deep sea rescue diver Jonas Taylor is recruited by a visionary Chinese oceanographer to save the crew and the ocean itself from this unstoppable threat that is a pre-historic 75-foot-long shark known as the Megalodon.

A battle-weary Marine is assigned to guard - and ultimately befriends - a young Navajo soldier who has been trained to be a code talker. This code, the Navajo code, and the men who knew the code, were to be guarded as they went into action. It was the unspoken duty of the Marine to kill the Navajo soldier before he could be taken prisoner of war by the Japanese. This is the one wartime code that was never broken by the enemy.