A father who experiments with his son's psychokinetic powers is unaware that these experiments have released a demon from hell which lives in his son's closet, preparing to take over the young boy's soul.

A number of vicious murders occur in a small California town after a motorcycle-riding stranger arrives. The gruesome slayings look disturbingly like the work of a werewolf. Meanwhile, in another nearby town, police are hot on the trail of a killer they believe is a werewolf.