Fred Baumann, a CPA, picks up a young female hitchhiker named Joanne. They park in his car and she seduces him, but then changes her mind. However, Fred's blood is boiling and despite her attempts to fight him off, he rapes her. She threatens to report him to the police unless he pays her $20,000. He realizes she has set him up for blackmail, but, since a rape charge would ruin his career and home life, he agrees to pay $5,000 immediately and $100 a week until the end of the year.

Meanwhile, we learn that Joanne usually only gets a few thousand dollars each time she pulls this blackmail caper, which is more than she normally gets as a stripper or a streetwalker. Since she was nineteen years old, she has been working in the sex trade and giving her money to her boyfriend in money, in return for his physical attention in between his other girlfriends.

We also learn that Fred Baumann’s wife, who has not been intimate with her husband, has been having a string of one-afternoon-stands with delivery men and repairmen and anyone else who shows up at her door. Their 15-year-old daughter, Karen, is apparently a good girl but has rape fantasies. One night she is gang raped by a group of boys, and surprises them all by encouraging them. The situation gets out of control and lasts for hours of terror, and ends only when the police arrive to break up the party.

Finally, Fred decides to murder Joanne because he can’t afford to keep paying her.