The special effects were handled by Rick Baker : his work was rewarded with a prize Academy Award for Best Makeup .

Seventies . David Kessler and Jack Goodman are two young students Americans traveling to the ' England 's north, in the English county of Yorkshire , for a vacation of three months. One evening, seek shelter in a small pub called "The Slaughtered Lamb" of a village called East Proctor, but the locals are very hospitable but not with them (in fact they are hunted for having asked about a pentacle placed on a wall, that in fact served to ward off demons and werewolves ). They decide to leave, but before they are advised to stay on the road and not venture into the heath .

It's a night of full moon and the two boys seem to have forgotten the advice, when they hear claims howls think we should go back to the pub but you realize that they are right in the middle of the moor and fail to orientate. They are attacked by a mysterious beast that kills Jack and David was seriously wounded, but he is saved because the beast is killed by gunfire from the patrons of the pub rushed to help. Before losing consciousness, rather than a beast David sees a naked man on the ground dying riddled with bullets.

David is admitted to a hospital in London and when he wakes up, three weeks later, he was told by the inspector of Scotland Yard Sir Villiers and Sergeant McManus who was attacked by a crazed maniac and that the police are investigating the incident. During hospitalization, David began to have terrible nightmares, dreams of chasing a deer for a bush and then devour him alive and in another he sees himself in the woods lying on the hospital bed, with a devilish grin on his face, then dreams even the monstrous Nazi soldiers brutally attack and kill him and his family because of the Jewish religion . Things get more ambiguous when David gets a visit from the ghost of Jack amputee who tells him that the two of them were attacked by a werewolf and that soon, with the next full moon, he will turn and kill the innocent; to break the spell in which all end up the victims, David must die.