The Russian Akula-class submarine's orders were simple: escort the cargo ship Turgenev across the Atlantic and safely deliver her to Cuba's shores. But someone aboard has a competing mission-sabotage. Now a fiery explosion has punched through its titanium hull, turning the once-prized vessel of the Russian fleet into a watery tomb. 100 ft down and sinking fast, two lone survivors remain, a Russian sailor and an American spy, the final combatants in a warzone only four hundred feet long and forty feet wide. Locked in heated battle, and buried under the weight of an entire ocean, each man is determined to kill the other before time runs out. But the fight to survive only starts on the ocean floor as these two men are pushed to their limits and beyond in a fight against each other, the deadliest environment on Earth, and their own military forces to complete their missions and make it out alive as the world hangs in the balance.