The film follows seven medical students who, while out partying one night, spike the drink of an unknowing and loner hospital janitor Kenneth, nicknamed "Freakdog". However, he has epilepsy and goes into a seizure before falling and hitting his head. His injury, combined with the alcohol and the drugs that he has ingested, causes him to fall into a deep coma. The students, not wanting to be involved or risk their futures for their crime, abandon his body on a road in front of the hospital and drive off as fast as they can, hoping someone will come across his body and help him. When they learn about his condition becoming fatal, one of the students (Arielle Kebbel) attempts to revive him using an experimental drug. The result has horrible and unintended consequences, leading to Freakdog having out of body experiences that allow him to possess the students who poisoned him and abandoned him. He exacts vengeance by possessing their bodies and through them, framing them for murdering each other while they desperately search for a way to stop him.