The film begins with Howard Griffin and Elizabeth Griffin having a romantic night out on a yacht near the Pacific Northwestresort community, Graves' Point. After a freak occurrence causes the yacht to sink, the two are forced to head for shore in a lifeboat, only to be attacked and eaten by an unseen creature hours later. The next day, local fisherman Whip Dalton finds the empty lifeboat and discovers a large claw stuck into the boat. Whip sends the claw to a university to be analyzed and it ends up in the hands of marine biologist Dr. Herbert Talley, who comes to Grave's Point claiming it is from the tentacle of a giant squid. The islandharbor master Schuyler Graves hires Lucas Coven to kill the squid after Whip's initial refusal. Coven succeeds in slaying a squid and the carcass is promptly sold by Graves to Sea LandTexas owner Osborne Manning. The unmanned sonar detects another, much larger squid which remains unnoticed by the islanders. When Whip and Talley aren't allowed to see the squid to examine it, Dr. Talley organizes a submersible expedition to explore the squid's habitat. After analyzing the carcass of the dead squid, the scientists determine it is just a baby. The information comes too late, however, and the adult squid, the baby's mother, attacks the submersible, killing everyone on board. Whip angrily blames Graves for the incident which also resulted in the death of Whip's daughter's boyfriend. Graves then blackmails Lucas to resume the hunt for the adult squid or he'll shut Lucas down for illegal trap fishing. Dr. Talley explains to Whip that the giant squid is killing out of vengeance for the death of her offspring rather than hunger, and is now even more dangerous as a result. Lucas resumes the hunt along with Whip's friend, Mike, and another crew member named Scranton. After enduring stormy weather they decide to head back to shore and continue the hunt the next day. The Squid attacks the boat before they make it to shore, devouring Scranton and knocking a cargo net on Mike, injuring him. It then attacks Lucas in the helm who fires a couple of shots with his gun at its tentacles. The squid then bites a hole in the hull. With water pouring in, it pulls the entire boat underwater, drowning Lucas. Whip, after learning that Mike went out to help Lucas comes to the rescue and, finding Mike holding onto a buoy, pulls him out of the water and takes him to the hospital. Whip then agrees to go out and hunt the giant squid but only if he can use his boat and Graves goes with him. He is also accompanied by coast guard officer, Lt. Kathryn Marcus, Dr. Talley, and Manning. They plan to snare the squid, reel it in and shoot it multiple times with darts full of cyanide. The plan succeeds and the squid appears dead. But when the ship's engine breaks down, Manning reveals that he filled the darts with tranquilizer instead of cyanide so he could take the squid alive back to Sea Land. Graves tried to escape on a lifeboat as Whip cuts the squid loose just as it awakes. The squid soon chases down and kills Graves. The death of both Lucas and Graves gives the squid vengeance for its offspring's death but it resumes its attack on Whip's boat, killing Manning and then jumping on the boat. It then grabs Talley and eats him. A coast guard arrives in time in a helicopter to pick up Kathryn and Whip. As he boards the helicopter, Whip fends the squid off with an axe, chopping open several extra fuel drums and has Kathryn use a flare gun to light his boat on fire. The squid is unable to escape as an explosion blows up the squid's beak and lower body, killing it. The helicopter flies them back to the shore where they reunite with Whip's daughter Dana.
This TV adaption is very loosely based on Peter Benchley's novel of the same name. In the novel, the squid has much younger offspring which do not make an appearance until the end of the novel, and the titular squid is killed by a sperm whale, not by an explosion as in the movie. Many storylines and characters are added or changed in the TV adaptation. For one thing, the book took place in Bermuda while the movie took place in a Pacific North West community resort called Grave's Point.
