In a remote laboratory, a Russian geneticist Dr. Vladimir Petrov administers an experimental serum to an old man who suffers from a rare genetic disorder called Krabbe Disease. The serum transforms the old man (Mr. Luca) into a werewolf. The werewolf escapes out the window.
Tom Randall fulfills his lifelong dream of being promoted to CEO of his company. His life tends to leave him empty and sad. He is famous for his one-night stands with women. After being dumped on Christmas Eve, Tom comes across a horrific scene blocking the road. After calling the police Tom is mauled by the werewolf who got loose. The police kill the beast and rush Tom to the hospital.
Tom wakes up in pain and transforms into a werewolf and jumps through the window and runs off into the shadows below. The werewolf saves a blind old lady from being mugged by thugs.
Tom wakes up all bloody, remembering the night before and how he killed some people. The murders are all over the news.
Tom tries to go back to work but Detective Jake Miller who is investigating the murders comes around to question Tom.
Jake questions Elaina the beautiful psychic Gypsy. She is Mr. Luca’s daughter. She feels responsible for Tom’s affliction.
Elaina reaches out to Tom to help him with his condition. Tom takes some time away from work to figure out a way out of his mess. He inadvertently causes the heart attack of his boss.
Elaina takes Tom to seek the help of Dr. Petrov, who has been performing illegal experiments on people to cure his own paralysis and created a hoard of genetically mutated creatures that he plans to release upon the citizens of Los Angeles.
The police show up at the abandoned Linda Vista Hospital and force a confrontation with Petrov and his beasts.
A battle ensues between the police and the beasts. Tom gets loose and rescues Jake and Elaina. Natasha injects her father, herself, and Cyrus with the serum. They tune into werewolves. Dr. Petrov bites off Jake's arm and Tom kills Petrov. He then gives chase to Natasha, Cyrus, and four other beasts on the rampage killing at will. Cyrus hijacks a truck that takes them to Hollywood Hills. Tom faces them in a fierce battle between him and the four beasts. Smashing through houses and ending up in a pool. The werewolf takes on Cyrus and kills Cyrus. The werewolf chases Natasha and she is killed by a four-wheeler.
Jake retires and stays quiet about Tom’s ability. Tom and Elaina drive off into the sunset.
