Growth

In 1989, Mason Lane conducts a parasite-based experiment on Cuttyhunk Island, aiming to accelerate human evolution. The attempt yields stronger, smarter, and healthier humans, but the project goes catastrophically wrong. Three quarters of the island's residents die, leaving the community devastated and the science agenda tainted.

Two decades after the disaster, Jamie, Kristen, Marco, and Justin travel to Cuttyhunk Island for a visit. Jamie wrestles with painful flashbacks about her father's project and its impact on her family. The group confronts the island's haunting legacy while dealing with personal tensions.

Larkin, another scientist from the project, visits Jamie and informs her that she will lose money from her Cuttyhunk inheritance. The news heightens fear of being drawn into the project again and fuels the group's distrust of the others. The confrontation sets the stage for further threats on the island.

By the river, a mysterious figure releases a parasite toward Justin, infecting him. The parasite accelerates his senses and power, pulling him toward unpredictable and dangerous actions. Kristen and Jamie observe the escalating threat as the group struggles to understand what happened.

Back in town, Justin's enhanced abilities allow him to dominate a bar fight with ease. He even corners the opponent's girlfriend and behavior grows increasingly dangerous as the parasite's influence deepens. The night ends with a disturbing display of power.

The following morning Justin wakes, unsure whether the previous night’s events were real or a dream. The parasite's ominous control lingers, hinting that his newfound abilities carry a heavy cost. The group begins to realize the infection is spreading among them.

Kristen discovers a cemetery filled with 1989 dates, hinting at the long reach of the project. The mysterious figure attacks her, forcibly injecting a parasite into her mouth. She fights to survive as she is drawn further into the island's dark history.

Jamie and Marco confront Larkin and Dr. Macavire, who ask to see Justin. The uneasy meeting reveals the scientists’ ongoing interest in the island’s dangerous technology. Jamie and Marco hurry to warn Justin about potential threats.

As Jamie and Marco attempt to warn Justin, the mysterious figure abducts Jamie and takes her to his house. The abduction escalates the group’s peril and signals the antagonist’s direct involvement in the island’s secrets. Justin remains unaware of these events as he deals with the parasite's effects.

Justin discovers Kristen's mutilated body just as approaching militia forces close in. He kills the militia, but Marco is killed in the crossfire. A policeman shoots Dr. Macavire after noticing a parasite sliding up his leg, eliminating one more threat.

The mysterious figure reveals himself to be Mason Lane, Jamie's father, and explains he developed an antidote formula. He contends that the antidote could reverse the parasite's effects and save Jamie.

Jamie escapes with the antidote and confronts Mason. She douses him in salt water, killing him and releasing the parasites within him. The act triggers a final scramble as the remaining parasites surge.

Larkin and Jamie escape the lab as parasites swarm behind them. Larkin urges Jamie to take a boat and flee the island. Justin emerges to stop them and ends up killing Larkin, while Jamie pleads not to be left behind.

Jamie escapes without Justin, but discovers she is infected as well. She leaps into the sea to destroy the parasites, sacrificing herself to save others.

An epilogue set in South Korea six months later reveals that the parasites remain active, suggesting the threat persists beyond the island. The closing image hints at a broader global danger and unresolved consequences.