Tim Ochopee, a Seminole Indian, has returned to the Everglades after serving in Vietnam and resides in an isolated shack, far from his tribe or any other people. Embittered by his experiences, the reclusive Tim rejects overtures by visiting Seminoles to return to their home village. Tim explains that his pet rattlesnake, Stanley, has taught him the true meaning of friendship and love, and that being forced by whites to kill “the yellow man” has eradicated his “sense of equality and brotherhood.” After the men leave, Tim goes inside, where he lives with Stanley and the snake’s mate, Hazel, as well as dozens of other reptiles. Tim is also visited by clothing entrepreneur Richard Thomkins, who specializes in supplying animal skins, and his assistant, Crail Denning. Tim is angered by the racist Crail and the arrogant Thomkins, especially as, a few years earlier, Crail “accidentally” shot and killed Tim’s father, and was cleared by the courts because he allegedly mistook the man for an alligator. Thomkins has learned of Tim’s return to the Everglades from Dr. Everett, to whom Tim supplies snakes for their medicinal venom, on the condition that they not be harmed. Tim rejects Thomkins’ offer of employment as a hunter, after which Crail and Thomkins depart. Tim then discovers that Hazel has given birth to three babies, and he celebrates with her and Stanley. The next day, Tim takes Stanley with him to town, where he gives a shipment of snakes to Dr. Everett. The physician shows him how the snake are handled delicately while their venom is being drawn, then explains that he told Thomkins about Tim’s whereabouts because he thought that Tim needed the money. He encourages the younger man not to take life so seriously, especially as he has been suffering from severe headaches, but Tim insists that no animal should be slaughtered needlessly. Tim then visits Gloria Calvin, a stripper who was once friends with his father. Tim continues to supply Gloria with live snakes for her act, despite the disparaging, racist remarks of her husband Sidney. After Tim resists Gloria’s attempts to seduce him and leaves, Sidney concocts a new, daring act for her involving the snakes. Later, Tim sees one of Thomkins’ vans near the swamp and discovers that it is filled with caged snakes. When Tim frees the snakes, he is attacked by Crail and Thomkins’ other henchman, Bob Wilson. After Bob pins Tim to the ground, he reveals that Tim’s father used to work for Thomkins, poaching animals from Seminole lands in order to put Tim through college. After Tim graduated, however, his father threatened to inform the authorities about Thomkins’ activities, so Bob and Crail killed him. As Tim struggles against his tormenters, Stanley bites Bob, enabling Tim to escape. The next morning, Crail and Bob tell Thomkins about their confrontation with Tim, and the fact that they revealed the truth about his father. Thomkins, worried that Tim will exact revenge, warns Crail and Bob to be careful when they are in the swamp, because of Tim's superior knowledge of the terrain. Thomkins is also anxious about his teenage daughter Susie, with whom he quarrels frequently about their clashing values. Meanwhile, Gloria complains to Sidney that she is repulsed by the new act, but he insists that it will bring them great wealth. Soon after, Crail and Bob hunt for snakes in the Everglades and this time are accompanied by Marty “Psycho” Simpson, one of Thomkins’ factory workers who is infamous for his drug-taking and his evil temper. Crail and Bob leave the stoned Psycho to guard their truck, and six hours later, they have captured numerous snakes. Upon hearing the poachers’ gunshots, Tim and Stanley investigate, and Tim uses Stanley to lure Crail and Bob into a patch of quicksand. The two men beg Tim for help but he instead orders Stanley to bite them if they reach for solid ground. Later, Psycho begins to wander, eventually finding his way to Tim’s shack, where he bludgeons the baby snakes to death and shoots off Hazel’s head. When Psycho emerges, carrying Hazel’s corpse, Tim, in a blind rage, attacks the hunter. After a fierce struggle, Psycho is about to decapitate Tim when Stanley bites and kills him. Deranged by the deaths of Hazel and the babies, Tim drives to Gloria’s club and is horrified to see that her new act consists of her biting the head off a live snake. Tim waits until dark and, while Gloria and Sidney sleep above the club, sends in various snakes to murder them. The next day, Tim sneaks onto Thomkins’ estate and releases water moccasins into his swimming pool. Not noticing the snakes until he has already begun his dive, Thomkins is killed, after which Tim kidnaps Susie and takes her to his shack. Although dismayed to be so far from other humans, Susie is intrigued by Tim and willingly goes to bed with him. When they awaken, Susie mentions that she will be leaving to join a commune, and Tim reacts angrily. Telling her that he wants her to join his Eden, Tim states that they will raise children who love snakes and hate human beings. Susie retorts that Tim merely uses the snakes as slaves to commit his murders, just as his sergeant in Vietnam used him to kill others rather than do “his dirty work” himself. Explaining that he does not feel human and that he dreams about being a snake, Tim begs her to stay, and when Susie demurs, Tim orders Stanley to kill her. After Stanley refuses, Tim tries to get several other snakes to carry out his orders. When they also fail to act, Tim beats them to death, then raises a chair to attack Stanley. As he stares into Stanley’s eyes, however, Tim realizes that he cannot kill his best friend. When Tim apologizes to Stanley and pleads for forgiveness, the reptile suddenly strikes, biting Tim in the eye. Stanley strikes repeatedly, wounding Tim severely and causing him to knock over a lamp and start a fire. Susie manages to escape from the locked shack and stands on the shore, screaming, as reptiles flee the burning building. Slowly, the dying Tim crawls outside and, as he reaches for Stanley, he muses, “Maybe in hell, I’ll find out what I am.”