17 user 10 critic

Elementary, Dear Data 

An attempt to provide Data with a challenging Sherlock Holmes holodeck RPG scenario backfires when its Prof. Moriarty character accidentally becomes self-aware.


Rob Bowman


Gene Roddenberry (created by), Brian Alan Lane




Episode complete credited cast:
Patrick Stewart ... Capt. Jean-Luc Picard
Jonathan Frakes ... Cmdr. William Riker
LeVar Burton ... Lt. Geordi La Forge
Michael Dorn ... Lt. Worf
Marina Sirtis ... Counselor Deanna Troi
Brent Spiner ... Lt. Cmdr. Data / Sherlock Holmes
Wil Wheaton ... Wesley Crusher (credit only)
Diana Muldaur ... Doctor Pulaski
Daniel Davis ... Professor James Moriarty
Alan Shearman ... Inspector Lestrade
Biff Manard Biff Manard ... Ruffian
Diz White Diz White ... Prostitute
Anne Ramsay ... Ensign Clancy (as Anne Elizabeth Ramsay)
Richard Merson Richard Merson ... Pie Man


When the Enterprise arrives a few days early at its rendezvous point to meet the USS Victory, the crew have a bit of leisure time on their hands. For Data and Geordi Laforge, it means a trip to the holodeck and 221B Baker St. With Data in the role of Holmes and Laforge as Dr. Watson, they take on a challenge from Dr. Pulaski that Data couldn't solve a genuine mystery. Data has a bit of time adjusting to a real mystery - as opposed to one for which he knows the outcome. In giving the holodeck computer its instructions however, Geordi's specifications for an opponent results in a far superior creation than expected putting them and the entire ship in danger. Written by garykmcd

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Did You Know?


The title parodies the expression "Elementary, my dear Watson" which was created for movie adaptations of the Sherlock Holmes character. The line does not appear in the original Sir Arthur Conan Doyle stories. See more »


The computer tells the senior staff that the override protocol was initiated under the authority of Lieutenant La Forge. So La Forge has the authority to shut it down, but no such attempt nor its aftermath are shown. Only Data was shown as unable to shutdown the Holodeck. See more »


Moriarty: If I destroy these surroundings, this vessel, can you say that it doesn't matter to you? Interesting pun, don't you think? For matter is what I am not.
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Referenced in Star Trek: Lower Decks: Moist Vessel (2020) See more »


Star Trek: The Next Generation End Credits
Composed by Jerry Goldsmith and Alexander Courage
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User Reviews

Wholesome and wondrous in all the best ways
9 April 2021 | by romeroposadadanielSee all my reviews

This episode shows TNG tackling big questions on consciousness and being, arriving at a warm, wholesome ending where curiosity and love of being alive are enough to make an entity "good'

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Release Date:

5 December 1988 (USA) See more »

Also Known As:

Elementary, Dear Data See more »

Company Credits

Production Co:

Paramount Television See more »
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Technical Specs


Sound Mix:




Aspect Ratio:

1.33 : 1
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