Bywater's native Seminole Indians believe the swamp will be bloodily revenged by its guardian spirit, a 'dark warrior', for its 'rape' by Frederic and son Jake Schist's oil-drilling, sold out by their own late chief Ted Sallis. The rig is illegally protested against by hot-head ecologists, who get blamed for vandalism on the site. New, outsider sheriff Kyle Williams suspects immediately local adolescent Billy James wasn't eaten during love-making there by a cayman but by a mysterious monster, which already made and soon makes new bloody victims in weird, inconsistent ways. Several people add to the danger.