| Director | Wes Craven |
|---|---|
| Budget | $2.5 million |
After Hank, a scientist, is mysteriously killed while assisting a top-secret bioengineering project, government worker Alice Cable arrives at the bogs to serve as his replacement. Alice immediately notices that one of the team's swamp sensors has malfunctioned, and Harry Ritter reveals that Hank was attempting to repair it when he was killed. Charlie tells Ritter a rumor about an evil paramilitary leader named Anton Arcane, who intends to hijack their operation. Alice introduces herself to Dr. Linda Holland and her brother, lead scientist Dr. Alec Holland, who takes her on a tour and encourages her to admire the beauty of the swamps.
After noting the disappearance of one of their workers, the group hears a loud bang and returns to the laboratory, where Linda shows off her recent breakthrough: a glowing, plant-based concoction with explosive properties. Sometime later, Alec notices that droplets of Linda's formula spawned rapid plant growth on the surfaces they touched. Suddenly, a group of paramilitary agents attacks her and raids Alec's laboratory. A man resembling Ritter steps forward, but pulls off his mask and reveals himself as Arcane. When Arcane shoots Linda for attempting to escape with the formula, Alec grabs the beaker, but trips, causing the spilled chemicals to set him on fire. He runs outside and dives into the swamp to extinguish the flames as a series of explosions bursts from the water.
Overnight, Arcane's henchmen destroy the premises and remove all evidence of the team's work. At dawn, henchman Ferret captures Alice and attempts to drown her in the swamp, but a green, humanoid creature rescues her. Meanwhile, in his mansion, Arcane and his secretary realize that Alec's most recent notebook is missing. Alice runs to a nearby gas station to telephone her employers for help; the operator connects her to Arcane, who, posing as Ritter, claims to have been called away from the site before the attack. After revealing she stole Alec's last notebook, Alice waits for Ritter's return alongside the young gas station attendant, Jude, but Arcane's men arrive and chase her through the forest. Suddenly, the green humanoid creature, referred to as the Swamp Thing, appears and again scares the pursuers away, and Alice escapes.
Alice and Jude boat around the swamp until they reach the dock near the laboratory wreckage. Multiple boats of Arcane's men close in on Alice and Jude, luring the creature from its hiding place among the reeds. Despite their bullets and grenades, the Swamp Thing arranges an elaborate boat crash. Moments after instructing Jude to escape with Alec's notebook, Alice hears the boy cry out in distress, but she is kidnapped before she can reply. The Swamp Thing finds Jude's lifeless body and presses a hand against his head, creating a greenish glow which instantly revives him. Regaining consciousness, Jude realizes the creature is a friend of Alice's and gives it the notebook for safekeeping. On Arcane's boat, Alice throws her kidnapper, Ferret, overboard, then dives into the water and swims ashore. Once on land, Alice bumps into the Swamp Thing, which calls out her name. Ferret chops off the Swamp Thing's arm with a machete, but the creature easily crushes Ferret's skull, causing Alice to faint. She awakens in the monster's embrace. The Swamp Thing speaks to her, and she recognizes it as Alec. Arcane's men follow her, capture the Swamp Thing in a net, and retrieve the final notebook.
That evening, Arcane invites Alice to a formal dinner party celebrating his duplication of the Hollands' formula. Moments after giving a toast to prospective immortality, Arcane reveals that he secretly slipped the first dose to Bruno, who begins to convulse. The hulking man's body shrinks to half its size as he grows pointed ears and a misshapen skull. Arcane locks him in a dungeon alongside the Swamp Thing, asking the latter why the experiment failed. The Swamp Thing reveals that the formula does not produce strength, but instead amplifies a person's natural qualities, explaining that Bruno's timidity caused his diminished stature.
After locking Alice in the dungeon with them, Arcane returns to his study and drinks a glass of the formula. A beam of sunlight emitted through the door re-grows the Swamp Thing's missing arm, allowing the creature to free itself, Alice, and Bruno. Upstairs, Arcane transforms into a hairy, boar-like beast and descends to the dungeons. There, he discovers that his captives have escaped through an underwater tunnel leading back to the swamp. Sometime later, Alice and the Swamp Thing emerge from the water, followed closely by Arcane, who stabs Alice with a sword. The Swamp Thing revives Alice and then kills Arcane. The creature turns to leave, but Alice pleads for him to stay so that she can help him rebuild his work. He refuses, but promises to return to her soon. Moments later, Jude emerges from the trees and embraces her as they watch the Swamp Thing lumber away through the marsh.