On the eve of his 78th birthday, the ailing, alcoholic writer Clive Langham spends a painful and sleepless night mentally composing and recomposing scenes for a novel in which characters based on his own family are shaped by his fantasies and memories, alongside his caustic commentary on their behaviour. His son Claude appears as a cold and unforgiving prosecuting lawyer, who revels in spiteful repartee. His second (illegitimate) son Kevin features as an idealistic soldier accused of the mercy-killing of an old man who was being hunted down. Sonia, the wife of Claude, shows sympathy with Kevin and seems eager to seduce him in protest at her husband's callousness. Clive also invents the character of Helen, as Claude's mistress, but she bears the features of Clive's dead wife Molly who committed suicide. Clive's imagination is also haunted by scenes of an autopsy on the corpse of an old man, a military round-up of elderly people who are detained in a sports stadium, and a dark tangled forest in which a hunted man metamorphoses into a werewolf. Before Clive loses consciousness, it is Kevin whom he sees as the werewolf in the forest; Claude shoots Kevin but seems to identify him with their father.