A team of animal activists, including Dr. Nikki Riley, Gia (Arden Cho), and Ben (Patrick Hancock), take drastic measures to combat the growing threat of invasive pythons in the Florida Everglades. They break into a house, steal dozens of exotic Python and set them free into the wild, believing they are helping the ecosystem. However, their actions have unintended and catastrophic consequences. The pythons grow to alarming sizes, becoming predators capable of killing large animals such as over 72 alligators within just a few days.
The situation quickly spirals out of control as the giant snakes and mutated alligators threaten to devastate the local wildlife and ecosystem. In response, Park Ranger Terry O'Hara (Tiffany), frustrated by the chaos and fearing for public safety, issues permits to local hunters to exterminate the pythons. Sadly, the hunters, including Terry’s fiancé Justin (Carey Van Dyke), are no match for the monstrous reptiles and are themselves slaughtered by the giant snakes shortly after beginning their task.
Determined to avenge her fiancé's life, Terry joins forces with co-Ranger Angie (Kathryn Joosten). Together, they resort to risky measures, taking anabolic steroids from Angie's grandson Manny (Chris Neville) to temporarily boost their strength, in hopes of facing the monstrous creatures. They feed steroid-laced chickens to the alligators, which results in increased aggression among the reptiles, further escalating the chaos. Meanwhile, [Dr. Nikki Riley] and her group set up surveillance cameras around the Everglades to monitor Terry’s activities and catch her in action—something they succeed at when they record Terry and Angie feeding steroids to the alligators.
Several months later, [Dr. Diego Ortiz] (A Martinez) warns Terry that an all-out war has begun between the massive pythons and ultra-aggressive alligators. Diego, examining the situation, urges Terry to cancel a fundraising event aimed at restoring a nearby estuary, fearing that the reptiles could attack the gathering. His warnings go unheeded. During their investigations, Nikki and her group stumble upon the skeleton of a giant python and are attacked, with Gia (Arden Cho) sadly being devoured by a large alligator.
In another part of the swamp, Diego makes a disturbing discovery: the alligators have laid hundreds of oversized eggs—some 20 to 30 times their normal size. Recognizing the danger, Diego requests permission to destroy the eggs with explosives, but his plea is denied. Flying over the swamp in a helicopter, Diego rescues Nikki but witnesses [Ben] being devoured by an alligator. After dropping Nikki off at her lab, Diego returns to the scene and destroys the eggs with dynamite, uncovering a cavern filled with thousands more massive eggs. He warns Terry that if she doesn't evacuate the upcoming party, he will alert the authorities and call in the National Guard.
At the extravagant fundraising event, chaos erupts. Nikki unexpectedly appears in the VIP tent, threatening to blackmail Terry with footage of her feeding alligators steroids, which leads to a fierce fight between the two women—tearing apart the celebration. Meanwhile, the reptiles crash the event in full force, attacking and devouring several guests, including the well-known Micky Dolenz, with only a few, like Barbara (Kristen Wilson), managing to escape.
Realizing they must act together to save Florida, Nikki, Terry, Angie, and Diego drive to Miami to seek help and stop the reptiles from spreading further. Their efforts are thwarted when Angie is caught and eaten by a python. Nikki devises a daring plan to save the state: she plants explosives at the quarry where the eggs are hidden, while Terry and Diego fly over Miami in a crop duster, using pheromones to lure the reptiles away from critical infrastructure like the Turkey Point Nuclear Power Plant. Their plane is struck by a python and crashes on the highway, but Terry, with quick thinking, drives an abandoned car loaded with gasoline to use as a trap. She successfully lures the reptiles away from the plant, buying time for a desperate rescue.
In the cave with the eggs, Nikki finds herself surrounded by countless hatchlings and an aggressive alligator. Terry arrives just in time, rescuing Nikki by driving her car into the alligator. As the reptiles close in around the quarry, Nikki and Terry seek refuge inside a supply shed. In a heartbreaking moment, Nikki admits she was responsible for releasing the snakes—that her actions were motivated by her belief they could help the environment, though it cost her dearly.
A helicopter arrives to rescue Nikki, with Diego attempting to save Terry as well, but tragedy strikes when Terry is caught by an alligator and killed. Nikki blows up the quarry in a final act of desperation, destroying the remaining reptiles but is thrown off the helicopter as it crashes from the explosion. As she falls into a swamp, surrounded by shredded snakes and alligators, she gets bitten in half by a still-living python head.
In the aftermath, a year later, [Dr. Diego Ortiz] cuts a ribbon to inaugurate the O'Hara-Riley Estuary, a memorial named in honor of Terry and Nikki—symbolizing their sacrifice and the devastating events that transformed the Everglades forever. Their story is a stark reminder of the consequences of tampering with nature and the chaos that can ensue when creatures meant to be wild are pushed to the brink.
