Jonathan and Diane Carver are young doctors in a small town where reputations mean everything. Late one night after a party, the married couple are driving home on Highway 9. Jonathan is trying to stay awake under the influence of drugs and alcohol but appears to be losing the battle. He nods once and twice before hitting something on the road. Diane awakens from her sleep to a shocked Jonathan and an unidentified man lying in a pool of blood.
Instead of taking John Doe to the hospital, Jonathan and Diane decide to take the accident victim home secretly under their care. They have to avoid the police inquiries and the chance that they will lose their practice and medical licenses. John Doe lies in their basement in a coma. Jonathan has to fight his addiction to save his marriage and practice while trying to save John Doe's life.
Strange things start happening to the doctors and people close to them after John Doe's arrival. Everything points to John Doe as the cause of the bad events. Curious, they investigate who John Doe is. The doctors soon discover that John Doe has been dead for decades.
Desperate, they attempt unsuccessfully to rid themselves of this curse. Diane learns much later that everything that has happened wasn't a coincidence. She realizes it is a struggle of life and death against an inhuman force bent on taking over Jonathan's body. Diane and Jonathan must stop the curse before it’s too late.