Jack discovers the plans of Mark Cephalos - the man behind the helicopter attack on the Werewolf!
The Werewolf runs through the streets of Los Angeles, evading the police, until he reaches a wharf. As he stands on a dock, a helicopter drops a net on him, which he dodges by diving into the sea. After battling a shark, he reaches an empty beach where he passes out.
The next morning, now in his human form, Jack Russell is found by two surfers, who give him a ride to the home of his friend, reporter Buck Cowan. Also there is Jack's girlfriend Terri. Discussing the arcane book, Darkhold, Terri suggests they show it to Father Ramon Joquez, a priest who was also a university professor specializing in ancient languages. The trio make the drive to meet with Joquez, who agrees to attempt a translation.
A few weks later, Buck expresses his worries about Jack, but Jack insists he can't share his secrets. That night, the three are visited by a man named Cephalos, and his assistant, Louis. Knowing of Jack's curse, Cephalos states he has a matter to discuss with him, and Jack agrees to accompany the man. In his limosine, the stranger gasses Jack.
At Cephalos' home, a former mission, Jack wakes up, bound within a glass chamber in a laboratory. Cephalos explains he was a dwarf, until an experiment gave him his large muscular body, but his form ages at an accelerated rate. He aims to siphon the lifeforce of the Werewolf to reverse the aging, and so enters a twin chamber. Louis begins the process as Jack transforms. The Werewolf breaks free and fights Louis, a martial artist, until the energized Cephalos himself bursts out of his chamber. He battles the Werewolf till the latter loses consciousness.
After coming to, the man-beast finds the pair taking off in their helicopter. The Werewolf leaps into the cockpit to attack. Amid the chaos, the Werewolf leaps out, as the chopper crashes into the Hollywood hills.