Chesapeake Bay is a seaside town that relies on water and the dockside tourism it brings to the community. When two biological researchers find a staggering level of toxicity in the water they attempt to alert the mayor before the situation gets out of control. However, the mayor refuses to raise the alarm in fear of creating a panic among the citizens of the docile town.

As a result, a deadly plague is unleashed, turning the people of Chesapeake Bay into hosts for a mutant breed of parasites. Taking control of their minds, and eventually their bodies, the parasites soon cause the town to descend in absolute terror as they quickly realise the harrowing reality they are faced with.