Ambitious, but ill-educated, naïve, and immature, Clyde Griffiths is raised by poor and devoutly religious parents to help in their street missionary work. As a young adult, Clyde must, to help support his family, take menial jobs as a soda jerk, then a bellhop at a prestigious Kansas City hotel. There, his more sophisticated colleagues introduce him to bouts of social drinking and sex with prostitutes.

Enjoying his new lifestyle, Clyde becomes infatuated with manipulative Hortense Briggs, who persuades Clyde to buy her an expensive fur jacket. When Clyde learns Hortense goes out with other men, he becomes jealous. Still Clyde would rather spend money on the fur coat than to help his sister who had eloped only to end up pregnant and abandoned.

Clyde's life changes dramatically when his friend Sparser, driving Clyde, Hortense, and other friends back from a secluded rendezvous in the country in his boss' car, used without permission, hits a little girl and kills her. Fleeing from the police at high speed, Sparser crashes the car. Everyone but Sparser and his partner flee the scene of the crime. Clyde leaves Kansas City, fearing prosecution as an accessory to Sparser's crimes. This pattern of personal irresponsibility and panicked decision-making in Clyde's life recurs in the story, culminating in the central tragedy of the novel.