Description
Dr. Edwards arrives at a secluded island laboratory to examine Mr. Porter. Although Porter carries a deadly flesh-eating bacteria, he is asymptomatic and shows no signs of necrosis. Along with fellow researchers Camila and Bridgett, Dr. Edwards spends two months examining Porter in isolation. Porter continually asks to see his wife, but he is continually denied.
Marcus prepares to marry wealthy heiress Kate Arias in the Dominican Republic. Mark's best friend Dobs, his brother Josh, and Josh's girlfriend Penny charter a boat and take Mark to a supposedly unpopulated island for a low key bachelor party. While en route to the island, Penny, Mark's former flame, attempts to seduce him but is rebuffed.
Sympathetic researcher Camila creates a rapport with Porter. Frustrated with his confinement, Porter intentionally infects one of the researchers as he begins revolting against his continued isolation. Porter warns Camila that he is dangerous. Bridgett becomes infected.
Josh and Penny go snorkeling and see the decomposing carcasses of sea animals littering the ocean floor. When they return to camp, Josh and Penny discover strange rashes on their skin. While Josh performs oral sex on her, Penny begins spitting up large amounts of blood and her flesh starts melting. Josh radios for help and a voice claiming to be Dr. Edwards provides him with instructions.
Realizing that they need help but are stranded, Mark and Dobs search the island and find a bunker. Inside, the two friends discover research related to the bacteria. They also find mutated men who attempt to kill them. Mark and Dobs are able to escape them, but Dobs becomes infected.
The bunker turns out to be connected to Dr. Edwards’ laboratory. Josh reunites with Mark and Dobs and they find the researchers. After formulating a plan for extraction, Bridgett and Josh split off to gather Penny and wait for the boat on the beach. Dobs and Edwards also go on their own while Porter, Camila, and Marcus initiate the laboratory's self-destruct sequence.
Bridgett kills Josh and makes for the beach. Penny sees Bridgett trying to steal the dinghy and the two infected women fight to the death, dismembering each other in the process. Penny successfully kills Bridgett, but succumbs to her illness and dies on the shore. Edwards also manages to kill Dobs and escape to the beach with a rifle.
After rigging the lab to explode, Porter, Camila, and Marcus discover Dobs’ body and confront Dr. Edwards. Edwards prepares to shoot Marcus, but Porter produces a handgun of his own and kills Edwards after Camila tells Porter his wife has been dead the entire time and Edwards has been lying to him. Porter, Camila, and Marcus escape when the boat arrives.
On the boat, Porter gives Camila and Marcus each a bottled water to drink. Shortly thereafter, Camila and Marcus hear loud noises. They discover that Porter infected their water by injecting his blood into the bottles with a syringe before killing the boat captain and escaping in the dinghy. Camila and Marcus begin showing signs of infection. Flashbacks reveal that Porter stole a radio from the HAZMAT suit when he assaulted the researcher and used it to impersonate Edwards, leading Josh and the others to the laboratory. It is also shown that Porter infected a mouse which is what led to the initial outbreak. The movie ends with Porter heading to the mainland and the implication that Porter plans on spreading the infection to the world.
