Adventurer Dirk Pitt (McConaughey) works for NUMA (National Underwater and Marine Agency), a government agency working to protect all things water-related. An encounter on the Nile with a beautiful U.N. medical investigator and neurologist, Dr. Eva Rojas (Cruz), trying to find the cause of a strange epidemic (that is driving North Africans to madness) leads them to suspect a vast pollution problem on the continent that threatens to kill much of the world's marine life, and thus, the entire planet's ecosystem. Pitt leads a special team of experts on a super-equipped yacht on a race against time, and the plans of a money-hungry billionaire and his ally, a violent West African tyrant. Their search takes them through the Sahara Desert, to a vast gold mine run by slave labor, and perhaps even the answers to two of the greatest mysteries of all time... the vast post-Civil War plot to assassinate Abraham Lincoln (and its tie to a missing "Ironclad" battleship, The Texas), and the disapparance of a famous 1930s female pilot...