A group of friends – siblings Oscar and Karen, Beth and her marine infantry boyfriend Randy, and Randy's sister Emily and her ex-
Navy SEAL boyfriend Niles – are traveling through the backwoods town of Fort Collins, Louisiana. While stopping at a gas stationed owned by Chopper, Oscar discovers a shrine to a local legend, Lockjaw. The townies give the boys directions to a house built by Grimley, a local tourist attraction and urban legend. Oscar and Karen convince the group to join them. En route, Oscar tells them all the legend of Lockjaw: A long time ago, Grimley Boutine and his sister Caroline were the last two remaining members of their clan. The two were in an
incestuous relationship, and Caroline was pregnant with her brother's child. The day before their wedding, an
albino alligator dragged Caroline off into the swamp. Grimley sought out the gator in the hopes that he would find her alive, but instead he came across her in a cave being devoured by the gator. Going insane with rage, Grimley killed the gator with his bare hands, before eating its flesh, then consuming the flesh of his sister, along with every other piece of flesh in the cave, slowly devolving, becoming half-man, half-alligator himself. The others do not believe his story. They arrive at Grimley's house, unaware that they are being watched. They set up camp for the night near the Grimley house for an evening of drinking and having fun. Meanwhile, one of the shop patrons, Grover, is slaughtered by an unseen beast on the riverbank after ignoring warnings to not defy Grimley. Randy leaves the group to get more beer from the truck, returning just in time to interrupt Karen from having sex with a drunken Beth. Oscar, however, secretly takes photos of Niles and Emily having sex while masturbating. Karen finds him and begins stroking and kissing him, as they are secretly also committing incest. Oscar climaxes early, and the frustrated Karen walks off and before being knocked unconscious by Chopper, who approaches Oscar; Oscar and Karen are Chopper's children. Subservient to Lockjaw, Chopper takes Karen away. Randy witnesses this and sees Lockjaw before running off into the woods. Oscar collapses on Emily and Niles, claiming that Randy had attacked him; Niles leaves Emily to treat Oscar's shock as he goes off in search of Randy. Randy and Niles both encounter Lockjaw and run, coming across a highway that they had supposedly gotten far off track from earlier; they return to look for Emily, only to be stopped by one of the shop workers who holds them at gunpoint. Niles is able to kill him, but Lockjaw gruesomely murders Randy. Beth awakens to her tent moved to a dark cave, and she screams upon seeing Lockjaw feast at a victim. Karen, having been set up as a sacrifice to Lockjaw, has her feet cut off by her father to lure Lockjaw from the underground, saying that it must be done for the family. After he leaves, Lockjaw emerges from the cavern below the shack and seems to recognize her by the necklace Chopper put around her neck, the same one that belonged to his sister. Niles finds Karen dead when he comes across the cabin, and is attacked by a disillusioned Oscar but quickly dispatches him with Oscar's
machete. Afterwards, he sneaks into Lockjaw's cave to save Emily, but they are both captured by the cult, with Lockjaw throwing Niles into the river. Chopper tells Emily that Lockjaw has chosen her to become his next bride. Niles follows the party to a gathering ritual that will allow Grimley to impregnate Emily. During the ceremony, Niles fights Lockjaw and manages to knock him into a sinkhole. He unties Emily but Lockjaw pulls Emily into the hole, with Niles following. The next morning, Emily and Niles emerge from the sinkhole with Lockjaw's jaw, and drive off. Some time later, Chopper arrives at the refurbished Grimley cabin, where a celebration with the cult is occurring. Beth is revealed to be alive, with a mutated baby. == Cast ==