Dietz did not create a new Sherlock Holmes tale; he adapted existing material, notably an 1899 play co-authored by Holmes creator Arthur Conan Doyle. Basically, what we have here is the story "A Scandal in Bohemia," in which Holmes meets his match in the form of beautiful and wily opera singer Irene Adler, framed by elements of "The Adventure of the Final Problem," in which Holmes meets his match in the form of Professor James Moriarty, the "Napoleon of crime."
Each story holds an unusual place in the Holmes canon: Holmes is actually outwitted by Irene and fails to bring her to justice (not that she is a real threat to society), and he apparently dies in his effort to vanquish Moriarty, the two famously tumbling over Reichenbach Falls in Switzerland. Doyle had enough of Holmes and tried to kill him off, but fans insisted upon his resurrection three years later. Sherlock Holmes: The Final Adventure properly leaves the detective's fate in some doubt. (That's not a spoiler; you know this from the very first scene.)
In the play at hand, Holmes has helped Scotland Yard close in on Professor Moriarty's extensive criminal organization, and Moriarty is doing his best to have Holmes killed. Holmes asks his longtime assistant, Dr. John Watson, to help him flee to the Continent until the police can make all the necessary arrests. Before they can depart, the King of Bohemia arrives. He will soon wed a member of another royal family, but the nuptials are threatened by scandal. His former mistress, opera diva Irene Adler, may use an incriminating photo of the two of them for blackmail. The king pays Holmes handsomely to retrieve the photo; Holmes agrees, although, uncharacteristically, his interest may lie in the woman rather than in the case itself.
Meanwhile, Moriarty (a huge presence in Holmes lore, even though he appeared in only two stories) goes to elaborate lengths to destroy Holmes and hold his criminal enterprise together.
Dietz has done an excellent job of tying many elements together in an effort to satisfy Sherlock Holmes fans while creating a satisfying evening of theater for everyone else. Not everything works, though. Dietz crams as many familiar elements as possible into the play--the cap, the cloak, the pipe, the violin, the index, "Elementary, my dear Watson"--and winds up spending all of 30 seconds on the detective's cocaine addiction, letting the subject pass without further mention or repercussions. Why bother? Also, why is Moriarty adamant about not firing pistols and drawing attention in a derelict warehouse district, but perfectly happy to pull the trigger in a respectable city residence? Why is the King of Bohemia marrying a Nordic princess in Switzerland? And why aren't Holmes' deep friendship with Watson and his infatuation with Irene, repressed as they must be, more fully developed?
That said, the story moves smartly under Goldstein's direction, and the actors fully inhabit their roles. As Holmes, Mark Capri vastly expands the one-dimensional characterization familiar from the old Basil Rathbone movies. This Holmes is focused and intense, but he also has a sense of humor that he sometimes, almost, seems willing to turn upon himself to alleviate some of his more melodramatic outbursts. Victor Talmadge is a solid, devoted Watson, a worthy companion to the detective. As Holmes tells him, "You are the one fixed point in this changing age," and we're willing to see that as a compliment rather than a warning of obsolescence.
Laurence Ballard brings to Moriarty a rich, well-oiled voice dripping with contempt; it's a performance reminiscent of John Colicos, a fine villain-actor best known, unfortunately, from the original Battlestar Galactica. Libby West is a steady, poised Irene, and Preston Maybank, Kenneth Merckx Jr., Erin Bennett and Roberto Guajardo do extremely well with their secondary roles.
Scenic designer Bill Forrester creates splendid and versatile Victorian interiors, and also nicely reproduces the actual contours of Reichenbach Falls. David Kay Mickelsen's costumes are everything that could be wished, right down to the Bohemian king's colorful quasi-Zorro outfit. Sherlock Holmes: The Final Adventure is light entertainment, but ATC offers it with affection and integrity.