On October 13, 2006, a university professor Diane Chasny and her nephew Ethan decide to examine the ecosystem of the Honey Island Swamp following Hurricane Katrina, especially the alligator populations. While attempting to test the sensitivity of her equipment, an alligator suddenly appears and destroys their equipment. As they try to find their way out, the nephew hears a strange sound, but dismisses it. They become lost, but luckily encounter a local fisherman Bud Ray, who agrees to lead them out of the area. The nephew hears more strange sounds and sees the obscured shape of a creature moving through the bush, and becomes briefly separated, accidentally stepping on a nest of eggs and destroying one of them. They discover a bizarre footprint that they conclude must belong to an upright animal, and the fisherman urges them to return to his camp. As the professor examines the photographs she took of the footprints, the fisherman tells them stories about the a creature purportedly half-man, half-alligator, but the professor dismisses these as being stories about a bogeyman. Around midnight, the fisherman wakes the two because of strange sounds that they heard, and he leaves the tent they had been sleeping in. There are strange sounds, gunshots, and a yell of pain as the creature attacks the fisherman, then tries to get into the tent. The fisherman returns, still alive, and the three manage to fend off the creature. The creature eventually leaves, leaving behind the egg the nephew had destroyed. The professor recovered the eggshells, which matched no known creature. The nephew returned to the bayou to create a feature documentary based on his experiences. The fisherman survived his injuries and still goes into the swamp, but is fearful of going out after dark.