They Might Be Giants (1971)

Synopsis
George C. Scott stars as Justin Playfair, a retired, widowed judge who labors under the delusion that he's Sherlock Holmes. Feigning concern, Playfair's greedy brother Blevins (Lester Rawlins) hires psychologist Dr. Mildred Watson (Joanne Woodward) to certify that Justin is insane--and in so doing gain control of the judge's millions. Instead, Dr. Watson is drawn into Playfair's dream world, accompanying the judge on his quest to find the elusive (and imaginary) Professor Moriarty. Reality rears its head when a group of vicious blackmailers, to whom Blevins is deeply in debt, attempt to assassinate brother Justin. In a sequence originally cut from the release version but restored for television, Playfair and Watson are rescued by a group of middle-aged eccentrics, who like the judge would give anything to live the lives of their literary favorites (the most poignant of these is librarian Jack Gilford, who "wishes to God" that he were the Scarlet Pimpernel). ~ Hal Erickson, All Movie Guide