Trapped in the submersible, Laura fears survival is impossible while Rich begins to hallucinate. Miles worries about Nimrod when he hears of trouble at the marine docks. Phil helps Miles look for Nimrod but they discover something else.

Laura and Rich are in for another shock when they leave the ocean floor and return to the surface. Meanwhile, Savannah suspects that Nimrod's responsible for Miles ending up in the hospital.

Rich and Laura try to get the footage of their trip to the ocean bottom to a news station before Lee can stop them. Meanwhile, Miles must watch as doctors prepare Nim for an autopsy.

On the run with Rich, Laura encounters a mysterious person who claims to know the origin of the creatures. Meanwhile, Miles fears the worst when two of Caitlin's friends vanish at the beach.

The search for the mysterious force responsible for the creatures leads Laura and Rich to an abandoned lab. Meanwhile, Miles joins the aquarium crew in searching for the field of unhatched eggs.