The mutilated former actor, now known as Atlas, murders movie producer Simon Kolb in cold blood - and Jack Russell is taken in for the crime!
With the first full moon of the month rising in the evening, Jack Russell goes to the home of his friend Buck Cowan where they've converted a storage room to a cell in which the Werewolf is to be caged. Before entering, Jack hands Buck a pistol and silver bullets, which he reluctantly accepts. The moon rises, and Jack transforms within the cell. Unable to break the bars, the Werewolf instead busts through the door. Buck is unwilling to shoot his friend and is slashed as the Werewolf leaps through a window.
In the mansion of movie producer Simon Kolb, Kolb is confronted by a hooded man in a toga calling himself Atlas. The stranger removes his hood to reveal a hideously scarred face, and Kolb remembers him as Steve Rand, an actor whose career was ended in a freak accident. Wielding an ass' jawbone, Rand then bludeons Kolb to death.
Soon, LAPD Lt. Victor Northrup's investigation into the disappearance of his partner Lou Hackett is interrupted by a call regarding Kolb's murder.
Seeking the forest, the Werewolf makes his way onto Kolb's estate, where he stalks and attacks Atlas. The powerfully muscled actor nearly drowns the man-beast in a fountain, then beats him to unconsciousness with the jawbone, and finally leaves him for dead.
Before long, Northrup and the police arrive to investigate the producer's death. They find the again-human Jack, as he recovers from his beating. Northrup tells Jack he's to be taken in for questioning.