The story follows David Kessler (David Naughton) and his friend Jack Goodman (Griffin Dunne), two American college students traveling through the English countryside. While hiking in the moors, they are attacked by a mysterious beast. Jack is killed, and David is left severely injured. After the attack, David is hospitalized in London, where he begins experiencing disturbing dreams and hallucinations.

As David recovers, he discovers that he has been transformed into a werewolf. Jack’s ghost visits him, revealing that David is doomed to become a werewolf during the full moon, and he must find a way to end the curse.

Meanwhile, David starts a romantic relationship with his nurse, Alex Price (Jenny Agutter), and struggles to come to terms with his terrifying new reality.

The film is celebrated for its groundbreaking special effects, particularly its werewolf transformation scenes, which were created by special effects artist Rick Baker.

The transformation sequence is often cited as one of the greatest in horror cinema. The film’s blend of dark humor and horror also set it apart, providing a unique balance between scares and laughs.