Two American college students, David Kessler (Naughton) and Jack Goodman (Dunne), are backpacking across the Yorkshire moors when they are attacked by a large, unknown animal. Jack is killed, but David survives the mauling and is taken to a hospital in London. When he wakes up some time later, he does not remember what happened and is told of his friend's death. Things get stranger when he is visited by Jack's ghost, which takes the distressing form of a reanimated corpse, who explains that they had been attacked by a werewolf, meaning that David himself is now a werewolf. Jack urges David to kill himself before the next full moon, not only because Jack is cursed to exist in a state of living death for as long as the bloodline of the werewolf that attacked them survives, but also to prevent David from inflicting the same fate on his eventual victims.