A highly advanced submarine called the Hei Ten Shi leaves China on a secret mission to deliver an otherworldly cargo to the Mariana Trench in the South Pacific. But when something goes mysteriously wrong, the clandestine ship is discovered by patrolling U.S. Naval forces aboard the SSN Dakota which detect the ship's unusual acoustic signature. But before Dakota can investigate further, the Hei Ten Shi explodes. One year later, a CIA operative named Whitt Roberts is called down to a highly classified division of the CIA known as The Blackdoor Group. He has been charged with investigating the disappearance of the SSN Dakota and the unexplained illness still plaguing its crew. But the Blackdoor Chief knows more than he's letting on, and soon has Whitt deployed on a much more dangerous mission.