How did I get suckered into a crazy contest to determine which sex is superior? groans Jack Kileen. But Kileen, a San Francisco writer, and Dr. Laura Sanders, a feminist professor from Florida, are tricked into doing just that when they appear on a TV talk show and argue heatedly about male and female roles. The show's conniving hostess, Mari O'Reilly, sees the contest as the opportunity to pump up her sagging TV ratings while guaranteeing the winner will be female. A panel dreams up a series of tests based on ideas that flood in from the public. Soon a Challenge of the Sexes with a prize of $1 million is under way. As the competition between Jack and Laura seesaws, the odds change in Las Vegas. Meanwhile, a writer for a sleazy tabloid magazine infiltrates one of Laura's classes and fabricates a sensationalistic story that threatens to get her fired. Jack faces the problem of a growing attraction to the woman monitoring his contest efforts. The Challenge of the Sexes reaches a climax in a kayak race on a storm-tossed river in Costa Rica, where a hungry crocodile awaits dinner.