During the 1980s, a black market shipment of exotic animals docks at Emerald Isle, North Carolina. A driver transports several creatures to another location. Amid the drive, he notices a pungent scent and pulls the van over, assuming a crate of reptilian eggs has gone bad. He tosses them into the swamp, thinking they’re rotten, and drives off.
Nineteen years later, the Connelly family returns to the island for a vacation, despite growing concerns about a powerful oil company polluting the local environment. Patrick Connally, Kevin Zegers, and his dog Buster explore the area, where a small lizard is spotted. In an attempt to catch it, Patrick stays out later than planned, and his parents search for him. When Patrick heads home after hearing his parents call, he is attacked by an unseen predator. He barely escapes, but he witnesses his family being torn apart by the same creatures, leaving him in a state of shock.
Patrick’s grandmother reaches out to Dr. Victoria Juno, a young psychiatrist, to help him cope with grief. Jill Hennessy is introduced as the medical professional who will guide Patrick through his trauma, while his aunt Annie remains distant and openly skeptical of Victoria’s involvement. With the grandmother’s support, Victoria returns to the island with Patrick and Annie, stepping into the Connellys’ old vacation home.
At the house, Annie is wounded in a horrifying confrontation as growls echo through the night. Victoria tends her injuries, but Patrick experiences a terrifying flashback and, upon waking in the kitchen, is drawn to a frightening sight behind Victoria: a massive Komodo dragon. Annie is killed, and Victoria and Patrick escape, realizing there are multiple dragons prowling the island.
They locate Martin, the boat captain, severely injured. Driving in a panic, they nearly collide with Oates, Billy Burke, and his maintenance co-worker Denby, Paul Gleeson, who have been sent to eradicate the reptiles. Oates and Denby tend to Martin, who is dying from infections caused by bacteria in a Komodo’s saliva. They call Bracken, Simon Westaway, the man who hired them to eliminate the dragons, for support.
Bracken refuses to evacuate the island until all the dragons are killed. Patrick flees into the tall grasses, while Victoria tries to follow but is pulled back onto the road by Oates. Denby remarks that Patrick had cut out the heart of a Komodo dragon during a previous confrontation. The group heads to the oil company’s station to seek shelter and medicine for Martin, who dies soon after, followed by Denby, who is attacked in another room. Bracken orders a helicopter to pick them up, while Oates reveals a complicated backstory: he used to be a biologist and his wife a geologist hired by the oil company to assess the environment; their separation left him with a tarnished image, and police suspect him of foul play in his wife’s disappearance. Bracken uses this to pressure Oates into handling the Komodo “problem.”
The team searches for Patrick at his old hang-out, a filtration center. Separated, Victoria is attacked by one dragon but saved by Patrick, who again helps her escape. Oates fights off another dragon, killing it, and then saves Victoria by shooting a second creature. They discover Patrick and Victoria explains that the oil company knew about the Komodos but concealed the truth to protect their interests, and that Patrick’s parents’ deaths were not his fault. As one dragon remains, Oates lures it toward leaking fuel and attempts to ignite it with Denby’s cigars. The plan backfires when the dragon survives the crude trap; Victoria counters by smashing part of a broom handle into the creature’s head after previously injuring it.
Finally, Bracken arrives with the helicopter, and Oates reappears alive to hijack the craft, leaving Bracken stranded with the dragons. Victoria and Patrick rush toward Martin’s boat to escape, but another large Komodo dragon closes in. From above, Oates fires a flare into the monster’s mouth, incinerating it. The pair reach the mainland unharmed, breathing a sigh of relief as the town returns to its quiet rhythm.
Back on the street, a sheriff checks in on them, and Patrick, with a calm resolve, asserts, “Never better.”
