Jessica Fletcher must diagnose a killer with a taste for bad medicine....

Bestselling author Jessica Fletcher is in Tampa with her good friend, Cabot Cove's own Dr. Seth Hazlitt, who is visiting a renowned Cuban physician. Alvaro Vasquez is developing a potentially groundbreaking cure for Alzheimer's disease. If he's successful, his American backers stand to make millions. But there is a growing fear that the drug may fall into the hands of a powerful pharmaceutical company.

Jessica attends a party at Vasquez's lavish home, but the celebration ends abruptly when guests witness Vasquez seemingly struck by lightning. Jessica and Seth do some digging into the physician's checkered past and learn that his death was no accident. As they work together to find a cure for the common killer, they begin to wonder if they'll ever see Cabot Cove again.