A group of friends travel to a remote Canadian island to hunt, only to be attacked by giant killer animals which have populated the place.
Morgan and his friends are on a hunting trip on a remote Canadian island when they are attacked by a swarm of giant wasps. Looking for help, Morgan stumbles across a barn inhabited by an enormous killer chicken. After doing some exploring, they discover the entire island is crawling with animals that have somehow grown to giant size. The most dangerous of all of these, however, are the rats, who are mobilizing to do battle with the human intruders.—Jean-Marc Rocher <[email protected]>
Off the coast of the Pacific Northwest, Morgan (Marjo Gortner), a professional football player, and his friend Brian (Jon Cypher), are on a ferry heading to an island for a few days' rest. Morgan remembers his father saying that someday nature will rebel against man for what man has done to it.
Meeting up with their teammate, Davis (Chuck Courtney), they all go deer hunting on horseback. Morgan corners a deer, then lets it go. Davis rides after it. Deep in the forest, Davis' horse spooks and throws him to the ground. He hears a loud buzzing noise and looks up to see wasps the size of buzzards. Morgan and Brian find Davis' swollen, dead body, and Brian stays with the corpse while Morgan rides to a farmhouse to ask for help. Mrs. Skinner (Ida Lupino), a farmer in her late fifties, sees him coming and runs into her house. Morgan knocks on the door, but gets no answer. Hearing a loud flapping sound, Morgan goes into the barn and sees six-foot tall chickens. The rooster attacks and Morgan kills it with a pitchfork.
Appearing in the kitchen window, Mrs. Skinner tells him he had no right to go into the barn. Morgan explains his friend is dead and he needs a phone. She says she does not have a phone, but asks him in to look at some holes in the wall. She thinks rats may have gotten in and eaten the chicken feed. Morgan sees a bowl containing a paste-like substance. Mrs. Skinner explains that it comes from the ground and makes animals gigantic. He watches a wasp eat the food and tells Mrs. Skinner that it is dangerous, but she says God gave it to her and Mr. Skinner because they are good people. She tells him that Mr. Skinner is in the city to sell it and make them rich.
Morgan and Brian leave the island. Afraid people will think they are crazy, they decide to let the coroner figure out what killed Davis.
On the night ferry, Mr. Skinner asks a ferryman if anyone has seen anything really big on the island. Meanwhile, Mrs. Skinner hears glass breaking in the kitchen and finds some canning jars overturned. As she cleans up the mess, two-foot-long worms bite her hand.
As Mr. Skinner drives home, he gets a flat tire. When he gets out to fix it, a pack of giant rats rush out and eat him alive.
The next day, Brian tells Morgan the coroner's conclusion that Davis had to have been stung by over two hundred wasps to account for the amount of toxin he had in his body. Morgan insists that they go back.
On the island, Rita (Belinda Balaski), a pregnant woman, and her boyfriend, Thomas (Tom Stovall), have gotten their recreational vehicle stuck in the mud. Jack Bensington (Ralph Meeker), a businessman, and Lorna Scott (Pamela Franklin), a bacteriologist, drive by, and although Rita tries to flag them down, Bensington is too busy to stop.
At the farm, Bensington and Lorna find the giant chickens torn to pieces, but Bensington thinks the chickens are fakes. They meet Mrs. Skinner and are told Mr. Skinner has yet to return. She then shows them a white fluid oozing from a rock. Mrs. Skinner explains that nothing will eat the fluid unless it is mixed with food, and it does not affect adult animals, only their offspring.
Morgan and Brian spot Rita and Thomas while driving on the island, and the couple tells Morgan about seeing rats the size of horses. Morgan wants the two to come with him, but they want to stay with the RV and ask Morgan to pick them up on the way back. When Morgan and Davis get to the farm, they see Bensington fighting off giant wasps with a shovel. After they shoot and kill some of the wasps, Bensington tells them to leave, saying he owns the fluid; however, Mrs. Skinner says no one owns it until Mr. Skinner says they do. Morgan explains he is only there to destroy the wasps' nest. Davis and Morgan find the nest and blow it up with a homemade bomb. Mrs. Skinner runs up and tells them Lorena has fallen down a rat hole.
Taking his shotgun, Morgan goes down the hole, but it caves in before he can rescue Lorna. Brian finds another rat hole and asks Bensington to go in with him, but Bensington calls him a fool. Morgan fights off three rats, but runs out of shotgun shells. Another giant rat attacks, and Brian appears, shooting it in the head. As they come out of the tunnel, Rita and Thomas run up to say rats are attacking their RV. Bensington wants to drive right through the rats, but Morgan tells everyone to stay put. Scouting out the situation, Morgan and Brian find a pack of rats ripping the RV into pieces.
Returning to the farm, Morgan discovers a fence that runs across the island with water on both sides. Brian says the fence will not hold the rats, but Morgan gets a generator to electrify it. Brian then points out that rats swim, but Morgan thinks they cannot as they have grown too big.
At the farm, Bensington scoops the fluid into all the containers he can find. Lorena asks him to help Rita, who is in pain, but Bensington ignores her, saying the fluid has stopped running and is drying up. The fence electrocutes some rats, and the remainder jumps into the water and drowns. Brian is ecstatic until Morgan says that not all the rats went into the water. They then realize the rats have short-circuited the fence with a tree. Before they can escape, the rats attack. Morgan fights a rat barehanded until he grabs a shotgun and kills it. He then watches in horror as rats devour Brian. Morgan jumps into the jeep and takes off.
When Morgan gets back to the farm, Bensington asks if Brian ran off. Morgan goes berserk and smashes all the containers of the fluid. As the rats approach, everyone runs into the house except for Bensington, who tries to salvage some of the fluid. The rats tear him apart. After a prolonged attack, the rats pull back, just out of shotgun range. Thomas believes a white rat is the leader.
During the lull in the siege, Lorna helps Morgan make bombs from black powder and gasoline. They kiss, and although she wants to make love, Morgan insists they wait until they get back to the mainland.
The rats renew the attack. Throwing a bomb, Morgan clears a path to the jeep. As he and Thomas jump in and speed away, the rats swarm the house, chewing through the wood. Mrs. Skinner kills a rat with a meat cleaver, but not before it tears her throat out. Lorena and Rita barricade themselves in the bedroom. Rita goes into labor and Lorna delivers the baby.
Meanwhile, Morgan and Thomas blow up a dam. Outracing the floodwaters, they rush to the house, fight their way back in and lead everyone upstairs to a small balcony. The flood hits and drowns all the rats except the white one. Out of ammunition, Morgan clubs the white rat to death with his rifle. When the waters recede, Thomas and Morgan pile the rats up and burn them. A few open jars of the fluid float downstream and go into a pond where cows are drinking. The cows are then milked and the milk is brought to a grade school where children drink it.
