Two American students are attacked while hiking on the moors in Northern England, with one being killed and the other mauled by an unseen assailant. The surviving student, David, begins having nightmares and sees visions of his deceased friend. He later discovers that they were attacked by a werewolf and that he is turning into one. The film is a comedy/horror that explores David's transformation and his difficulties reintegrating into society and dealing with his new werewolf nature.