Perry Mason is called in by the Safeline insurance company when they face a flood of questionable disability claims from men who have suffered heart attacks. What intrigues Perry is that the mortality rate among the victims is far lower than the actuarial tables would suggest. Paul Drake sets out to check on some of the claimants and finds one, Jack David, to be in very good physical condition. So Perry asks to have him come in to have the insurance company's doctor examine him. Jack calls Perry the night before the appointment but can't talk. He dies upon entering the doctor's office with his wife and lawyer before he can tell anyone what was really going on, though it's clear in Perry's mind that insurance fraud has been committed. Perry sends Della to an involved doctor, who appears to be a fake, for an exam. Paul Drake goes undercover on a construction site but he too seems to suffer a heart attack and is hospitalized. Perry goes into a Coroner's hearing intent on uncovering the truth.
—garykmcd