Synopsis

In the North Sea, a Navy submarine encounters a colossal underwater anomaly. Matt, Connor, and Abby are brought aboard to investigate, but their mission takes a perilous turn when the vessel is drawn through the anomaly into a prehistoric sea teeming with giant pliosaurs. The team now races against time to return to their own era, while Lester battles to prevent an Admiral from detonating a nuclear weapon within the anomaly, a move that could irrevocably alter the course of history.