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.

When a young journalist dies in violent circumstances, her brother soon learns, by way of the mysterious Stefan Crosscoe, that his sister has succumbed to the werewolf curse.