In Fly Creek, a storm knocks down the power lines, transforming worms in mutant creatures. Mick travels from New York to meet his girlfriend Geri Sanders and stays at her home with her mother Naomi Sanders and her sister Alma Sanders. On the arrival, Mick has a friction with Sheriff Jim Reston and with Geri's neighbor Roger Grimes that woos her. Soon they find that Fly Creek is infested of carnivorous worms that are devouring the inhabitants, but Sheriff Reston believes it is a prank of Mick.
At the beginning of the film, we learn from one of the characters that earthworms can be called to the surface with electricity, but somehow it turns them into vicious flesh-eaters. Sure enough, a storm that night causes some power lines to break and touch the ground, drawing millions of man-eating worms out of the earth, and into town where they quickly start munching on the locals.
Slightly tongue-in-cheek horror film about carnivorous worms brought to the surface by a fallen electrical wire that sends millions of volts of electricity into the ground near the vicinity of a sleepy fishing village in the US state of Georgia.
A storm causes some power lines to break and touch the ground, drawing millions of man-eating worms out of the earth, and into town where they quickly start munching on the locals.
- On the early morning hours on September 29, 1975, in Fly Creek, a small town near the coast in Georgia, a powerful electrical storm rages one night. The high winds topple large high-voltage power lines, and the wires drag and snake along the wet, muddy ground.
The next morning, Geri Sanders (Patricia Pearcy) awaits the arrival of her new beau, Mick (Don Scardino), a city boy she met at an antique show while vacationing in New York City. Mick arrives on a bus that is forced to turn back due to a large tree that the storm has knocked down across the road. Instead, Mick chooses to walk through the woods, where Geri is amused to find him sunken into a mud hole.
Geri lives with her mother, Mrs. Sanders, and her younger sister, Alma. Alma is jealous of the attention Mick gives Geri, and tries her hardest to appear more cultured and stylish, since she thinks Mick will respond to this being from the city. Also jealous of Geri's relationship with Mick is Roger Grimes (R.A. Dow), a slightly backwards neighbor who adores Geri. Roger has loaned Geri his father's truck to go and fetch Mick, and there is an immediate problem: Roger's father is a "worm farmer", collecting thousands of worms to sell as bait. The crated worms, which were in the back of the truck, are now missing, the crates empty. Mr. Grimes blames Roger, but Roger knows he loaned the truck to Geri. Roger blames Mick, the interloper who has designs on Geri.
The electricity is still out in the area; Mrs. Sanders asks Geri and Mick to fetch a large block of ice for the refrigerator, and while they are in town, Mick stops into a diner. When he orders an "egg cream", the waitress has no idea what he wants, but she does her best to prepare the drink the way he describes it. Mick is shocked when he finds a worm in the drink, spilling it all over the counter. The waitress is furious, and Mick scolds her for serving him a drink with a worm in it; however, the worm has disappeared. The local redneck Sheriff overhears the outburst and makes a thinly veiled threat to Mick for "being disruptive". The locals obviously distrust Mick because he is from the city.
Back at home, Mrs. Sanders is clearly spooked by the storm and the subsequent damage. She remains aloof and seemingly in her own world, and Geri admits that she has been that way ever since Geri's father passed away months earlier. The water service has been interrupted, too, and the shower does not work.
Geri takes Mick to visit the local antiques dealer, Mr. Beardsley, but he is nowhere to be found, his home mysteriously abandoned. Mick and Geri are shocked to find a skeleton in the flower garden behind his home. They run and fetch the Sheriff, but when they return with him, the skeleton is gone. The Sheriff is furious, thinking Mick is trying to make a fool out of him, and scolding Geri for being involved in a prank.
Later, Mick and Geri go fishing with Roger, and while he is unaware, they discover the missing skeleton in the back of his truck. Mick and Geri don't say anything about it to him. While they are out on the boat, one of the large sandworms they use for bait bites Mick on the arm. Geri explains that the worms in the area bite with sharp, pincer-like jaws, but the wound on Mick's arm is quite bloody. Geri admits she's never seen a worm bite like that, but Roger says he has. He tells Mick and Geri that when he was a child, his father used Roger's electric train transformer in an experiment to see if they could jolt worms out of wet soil with electricity. The experiment worked, but the worms were extremely volatile when they emerged, biting half of Roger's thumb off.
Mick has Roger take him back to shore and leaves Geri alone with him on the boat so that he can examine the skeleton. While he is in the truck, Alma appears and startles him. Together they remove the skull from the skeleton and take it to the local dentist's office, where they break in. Mick is convinced the skull belongs to Beardsley himself and that he has been murdered, and he confirms this through Beardsley's dental records. How he was reduced to a skeleton, however, remains a mystery, and furthermore why Roger had took the skeleton and hid it in the back of his truck.
Meanwhile, back on the boat, Geri and Roger are alone and Roger makes a pass at Geri. When she rebuffs him, Roger is furious and they struggle. Geri knocks him over right onto the worms, which have overturned their small container and have slithered across the floor of the boat. Geri is horrified when Roger turns over, the worms attached to his face, and she sees them burrowing under his skin. They both fall out of the boat and into the water, where Roger runs off screaming into the woods, leaving Geri alone. Geri returns home in a panic and tries not to alert the fragile Mrs. Sanders that anything is wrong. In an attempt to shower off the dirt from the lake, Geri discovers that the water is still not working; as she fiddles with the knobs, she does not see that directly above her, worms have begun to emerge from the showerhead. They dangle from the large nozzle openings, then retreat mysteriously.
Mick and Alma return home and Geri finds out that the skull belongs to Mr. Beardsley. Geri is horrified and upset; she also tells them what happened to Roger. The insane Mrs. Sanders appears suddenly and starts to realize something is wrong, but nobody will tell her anything out of fear of upsetting her.
Mick goes to the Grimes farm to see what happened to Roger, and he finds the body of Mr. Grimes. Thinking the old man had a heart attack, Mick puts his ear to Grime's shirt and hears a strange sound. Pulling the shirt open, he is horrified to see thousands of worms eating Grimes from the inside out.
When Mick returns to Geri, they deduce that Beardsley must have been killed by worms during the storm. They realize that Roger seems to have discovered the skeleton and taken it, mistaking it for one of Beardsley's antiques. They make one last attempt to convince the Sheriff, who is eating a spaghetti dinner with his girlfriend at a local restaurant. Skeptic, he angrily sends them away, threatening to arrest them.
Mick and Geri return home for dinner, when a large tree suddenly topples, crashing through the ceiling of the dining room. Nobody is hurt, but the side of the house is now ripped open and exposed. Mick goes around to the base of the tree and finds the upended root covered in worms. When he goes to get gasoline to burn them, he returns to find them gone. He deduces that what is driving the worms back is the light; it is still daylight, and light seems to keep the worms at bay. With the damage to the house, Mick goes off to find plywood to board up the openings; he knows that once the sun goes down, the worms will be free to attack once again. Geri sends him in the direction of an old mill that was torn down, but when he goes there he is attacked by Roger, who is now demented and behaving like an animal. He hurls Mick into a ditch and knocks him unconscious, leaving him for the worms that he knows will come.
Back at the house, Alma attempts to take a shower but also finds the water is still off. She does not realize the pipes are full of worms. Unlike Geri, she leaves the faucet open, and after she leaves, worms begin falling out of the showerhead. Eventually the showerhead breaks off completely, and a steady stream of worms gushes into the bathroom, which is now filling up with the things.
Roger, still with worms in his face, lurks outside the house in the falling darkness, while Mrs. Sanders begins to behave strangely, indicating that she's losing her grip on reality. When she sends Geri into the kitchen for something, Roger appears and grabs her. Mrs. Sanders and Alma aren't aware that he's in the house, and Mrs. Sanders mentions that she hears water running in the bathroom. Alma remembers she left the faucet on, and goes upstairs. But when she opens the bathroom door, a sea of worms pours out of the room into the hallway.
Other residents of Fly Creek are attacked by millions of worms. The Sheriff and his girlfriend, who are having sex in an empty jail cell, are consumed by a flood of worms, as are the patrons of the local bar.
Mick regains consciousness and finds himself surrounded by pools of worms. He saves himself by making a torch out of his shirt and fending them off with the light. When he goes back to the house, he finds worms pouring all around the place, covering the floor. They shy away from Mick's torch, allowing him to enter the house, where he finds the body of what used to be Mrs. Sanders, covered in writhing worms. Going upstairs in search of Alma and Geri, Mick is attacked by Roger, who emerges from the attic. He has kidnapped Geri and tied her up, keeping her hostage in the attic room. Mick drops his torch in the struggle; no longer able to fend off the worms, he cannot go back downstairs, and by now the entire downstairs of the house is literally engulfed in a sea of worms that almost reach the ceiling. When Roger tries to push him into the worms, Mick manages to throw him in instead, and the worms pull Roger underneath of them.
Mick unties Geri and they attempt to climb out of an upstairs window into a tree. Roger, however, has emerged from the sea of worms, crawling like a worm himself. He attacks Mick, who beats him to death with a flashlight. Mick and Geri escape into the tree.
The next morning, they awaken in the tree branch to find the sun has risen and driven the worms away. A representative from the electric company tells them the power is back on and the towers have been repaired; he remarks that the town seems deserted. Inside the house, a large steamer trunk opens and Alma emerges, still alive; she apparently managed to get inside before the worms engulfed her. Mick and Geri are ecstatic that she has survived, and they run inside to greet her.