Sweet young Melanie Blaine returns to her small backwoods country hometown of Gibbington to check on her estranged ex-sheriff father Howard, who's the primary suspect in a series of grisly murders. Nice guy local Jimmy Fuller helps Melanie out. Melanie eventually finds her dad and discovers that something not human and much more sinister than a mere mortal man is responsible for the killings.

Famed mystery writer, Mort Rainey (Depp) is confronted by a mysterious stranger outside his house. This stranger calls himself John Shooter (Turturro) and claims that Mort has stolen an idea for a story from him. Mort says he can prove he wrote his first, but whilst Mort waits for the evidence to appear, Shooter starts to become more and more violent.

Suddenly the US east coast is hit by a type of natural disaster formerly reserved, except after a major earthquake, for the Pacific and Indian ocean rims: tidal waves of the destructive tsunami type. Scientist and fiction author John McAdams attends a national emergency conference which concludes the phenomenon must be man-made, quite possibly abusing the findings of John's secret former Sea Lion project, but who wants to and has the means? Indeed John soon finds himself set-up for a murder and chased. Major destructions mean major contracts for construction and coastal defenses, so building tycoons like Victor Bannister certainly have a considerable interest...