Tom Wyatt has developed a treatment for gill fever, a disease in tropical fish. His friend and ex-boss Frederick Rollins has sold his tropical fish supply business to Jack Huxley who takes it from him and asks a chemist, Darrell Metcalf to analyze it and reproduce it for him. Wyatt and Rollins consult Perry Mason and are told that scientific discoveries done on behalf of the company become the intellectual property of the purchaser. Wyatt is angered by it all making off the cuff death threats and when Huxley is found dead, he is charged with murder. Wyatt is found with a cut hand that appears to have been cut when he broke a window into the Huxley offices plus Huxley's secretary Sally Wilson is engaged to Wyatt and forced to work late that night with Huxley who made a pass at her. Perry defends him and there are several others who would have liked to see him dead, including his wife Norah and his business partner who tries to steal the business with a story about a phony deal with Huxley's wife.
—garykmcd