Dr. Mark Sloan is a good-natured, offbeat physician who is called upon to solve murders.

In Los Rios enroute to Los Angeles, Carol makes an urgent call to her father, Dr. Mark Sloan, pleading for help. Arriving in the small, seemingly pleasant mountain town, Mark investigates but the whole community denies knowing anything about his daughter and her husband. Dr. Sloan, however, soon uncovers enough evidence to make him believe that his daughter and son-in-law may have met a tragic end.