Lake Placid 3 is set at the same fictional Black Lakein Aroostook County, Maineas the first two films.The film opens up with a truck labeled "Dimitri's American Market", where the owner is driving and two teenagers are re-kindling their romance in the back. The man says to the driver to stop the truck and leave them to relax down by the lake. The man and woman are seen having sex with each other on shore very close to the water, when something attacks the man and drags him into the water. It is estimated that four baby crocodiles have attacked and killed the man then swarm in and kill the woman as well.Back at the house of Sadie Bickerman, her son, Nathan (Colin Ferguson), his wife, Susan and little boy, Connor, have finished gathering all of Sadie's belongings and decide on whether or not they are going to sell the house. A pet lizard that has escaped from its cage is loose and Connor follows it all the way outside to the lake where the baby crocodiles are. Revering them as his new "pets", Connor secretly begins to feed the baby crocs with products such as beef jerky and frozen meat that Connor has stolen from the supermarket.Meanwhile, Nathan is out searching for a missing elk, only to find its severed head and wondering if it could've been the act of a cougar lady, Reba (Yancy Butler) or something else. Nathan calls for Sheriff Willinger (Michael Ironside) to help track down whatever it was that killed the elk. In a local bar, a teenager, Brett, has come to Reba for some assistance. To find his girlfriend, Ellie, who is somewhere on the lake. Reba agrees to help and brings in her two hunting partners along with her for the search.However, without warning, the crocodiles have been growing bigger and becoming more aggressive. One of the crocodiles attacks Reba's boat, killing one of her hunting partners and the three are stranded in the woods. Another crocodile attacks two high-school teenagers, leaving their two friends left out to fend for themselves. Back at Sadie's house, Connor is found by his mother who notices blood on his shirt and that his babysitters' right arm has been brutally bitten. Connor comes in and tells his family the truth, that he's been coming to Sadie's house with his bike and feeding the crocodiles food, that explains the reason why Connor tried to steal meat from the supermarket because, as he claims, "I couldn't feed them enough."Realizing what they're up against, Nathan suggests they should try to hunt down and kill the crocodiles before anymore people get hurt. Unfortunately, the crocodiles have grown smarter and kill Vica, the babysitter as well as Willinger who was dragged by the crocodile into the lake while sitting in the Bickermans' car. Meanwhile, Reba and her hunting partner, Jonas, are able to shoot and kill one of them, before another crocodile comes in and bites Jonas' head off and attacks Reba. Brett tries to shoot it, but accidentally shoots Reba instead. The two take Reba's boat and head for the Bickermans' house. Brett, who is very anxious to find Ellie, pulls out a shotgun to Nathan and takes his boat to go and find her. Brett succeeds, but not until another crocodile comes in and kills him, leaving Ellie out in the woods, alone.Meanwhile, another crocodile has broken into the house, but Reba is able to cut its head off with her knife. The five (Nathan, Susan, Connor, Ellie and Reba) leave the house and get onto Reba's boat where they head into town. There, they find that yet another crocodile has found them and they decide to take shelter in the supermarket. When the alarm has gone off, the store's manager, Dimitri, comes with his truck and is eaten by the crocodiles. The crocodiles then come into the supermarket to attack. Reba is able to slice one of the crocodiles with her knife but gets killed in the process. One crocodile is killed when a whole shelf of products comes down and falls right on top of it.With just one crocodile remaining, Nathan takes Dimitri's truck to the gas station where it crashes, but Nathan is able to pour gas on the crocodile until it begins to consume the whole gas pump. Connor throws Nathan a lighter, presumably Vica's cigarette lighter, where he tosses it into the crocodiles' mouth and explodes, with the remains of its body scattered all over the place. In the end, an ambulance comes in and helps take care of Ellie, Nathan, Connor and Susan.The next morning, Nathan, speaking in front of a group of tourists, announces that the main river crocodile has gone extinct, and takes them on a tour around the lake. The scene cuts to where we see a baby crocodile swimming as another giant crocodile jumps out of the water and attacks the camera. The film ends from there and the credits roll.