It seems likely the narrative was altered from the book's original form, because it’s hard to picture Alastair MacLaine crafting a story with such noticeable gaps in logic and moments where characters acted inexplicably foolishly. The initial scene feels disconnected from what follows, which is an obvious indication that it serves as an introductory explanation—a detail it revealed to me prematurely, spoiling a significant plot development. When the action finally starts, it launches into a protracted chase sequence featuring nearly every police vehicle in Louisiana; these officers appeared to lack communication, instead forming a neat line for easy incapacitation or submersion. I won't elaborate further on the storyline, both to avoid revealing more and because mentioning it would acknowledge that I viewed most of this disappointing film.

Source on TMDB