A missing 1950s era airplane is found 27 years later at the bottom of a lake. British and Soviet spy agencies are intensely interested.

A skeptical news reporter is invited by the CEO of Nexecon Petroleum to document the safety of Colossus, the largest drilling and refining platform ever constructed. As the powerful drill tears through the seabed, a fissure forms, revealing a hidden mirror ocean teeming with prehistoric life. When a team is sent to access the damage, it comes face to face with the most powerful oceanic predator that ever lived: Carcharodon Megalodon.

Charles Ryder, an agnostic man, becomes involved with members of the Flytes, a Catholic family of aristocrats, over the course of several years between the two world wars.