Less Than Zero is told from the first person perspective of Clay, the main protagonist. Clay is a rich college student returning to his hometown of Los Angeles, California for the winter break in the 1980s, during which he reunites with his friend Trent, a succesful model.
After the reunion, he begins a streak of wild, drug-fueled parties, where he meets and has one-night stands with various men and women. In the process, he attempts to find his ex-girlfriend Blair and his best friend Julian. In between parties, he also goes on a vacation with his family, during which is the only one who cares that his grandmother is dying.
Gradually, he becomes disillusioned with the apathetic attitude his friends adopt towards the plights of the people around them. At another party, he and Blair are the only two repulsed by the snuff film that Trent screens.
Eventually, he is able to find Julian, who has now become a heroin addict and prostitute.
Nearing the end of the novel, Clay becomes isolated and alienates himself from the party scene. With the break ending, Clay returns to Camden College back in New Hampshire.