The Titanic is under a new threat. Resting at over 12,500 feet below sea level and 380 nautical miles off the coast of Newfoundland, the most famous shipwreck in the world is being consumed by a colony of iron-eating bacteria. This slow and irreversible decay, according to the most concerned experts, will sweep away all the secrets of the mythic liner within a few decades. This documentary details the underwater odyssey of the greatest Titanic expeditions and the evolution of the most scrutinized shipwreck in the world. From the epic discovery of the wreck by a French-American team in 1985 to the exploratory missions led by James Cameron, and to the treasure hunts that brought back over 5,000 vestiges–experience the unequaled thrill of these extreme dives through the eyes of the explorers who have attempted to unlock Titanic’s secrets.

James Cameron teams up with NASA scientists to explore the Mid-Ocean Ridge, a submerged chain of mountains that band the Earth and are home to some of the planet's most unique life forms.

101-year-old Rose DeWitt Bukater tells the story of her life aboard the Titanic, 84 years later. A young Rose boards the ship with her mother and fiancé. Meanwhile, Jack Dawson and Fabrizio De Rossi win third-class tickets aboard the ship. Rose tells the whole story from Titanic's departure through to its death—on its first and last voyage—on April 15, 1912.