A widower starts to believe he is Sherlock Holmes, prompting his family to have him committed. A psychiatrist coincidentally named Watson is assigned to treat him, but becomes fascinated by his delusions and begins helping him crack the case he believes he is on. Romantic comedy mystery based on James Goldman's stage play, with George C Scott and Joanne Woodward.

After the death of his wife, retired judge Justin Playfair creates a fantasy world for himself in which he is the legendary detective Sherlock Holmes, even dressing like the character. Out of concern for Justin's money more than his health, his brother Blevins puts him under the care of psychiatrist Dr. Mildred Watson. As Dr. Watson grows fond of Justin, she begins to play along with his theories, eventually becoming an assistant in his investigations.