Elementary, Dear Data

"Elementary, Dear Data" is the third episode of the second season of the American science fiction television series Star Trek: The Next Generation, the 29th episode overall. It was written by Brian Alan Lane and directed by Rob Bowman. It was originally released on December 5, 1988, in broadcast syndication.

Set in the 24th century, the series follows the adventures of the Starfleet crew of the Federation starship Enterprise-D. In this episode, a holographic adversary is created on the holodeck of the Enterprise when Data and Geordi take some time off to play a Sherlock Holmes game. The plot line from this episode was continued in the sixth season episode "Ship in a Bottle", and the Moriarty character appeared a third time in "The Bounty" (the sixth episode of Star Trek: Picard season 3).

In 1989, "Elementary, Dear Data" was nominated for two Emmy Awards: Outstanding Art Direction for a Series, Richard D. James, Art Director; Jim Mees, Set Decorator and Outstanding Costume Design for a Series, Durinda Wood, Costume Designer; William Ware Theiss, Starfleet Uniforms Creator.

As the Federation starship Enterprise, under the command of Captain Jean-Luc Picard, waits to rendezvous with the USS Victory, Chief Engineer La Forge and Commander Data go to the holodeck to recreate a Sherlock Holmes mystery. Data, playing Holmes, has memorized all of the Holmes stories, and recognizes and solves the mystery within minutes. Frustrated, Geordi leaves the holodeck, leaving Data confused. In Ten Forward, Geordi explains that the fun is in solving the unknown; Data does not understand. Overhearing their conversation, Chief Medical Officer Dr. Pulaski asserts that Data is incapable of solving a mystery to which he does not already know the outcome. Data accepts Dr. Pulaski's challenge and invites her to join them on the holodeck. There, Geordi instructs the computer to create a unique Sherlock Holmes mystery with an adversary who is capable of defeating Data.

In the new program, Dr. Pulaski is kidnapped, and Data investigates. They soon discover that Professor Moriarty is responsible, but when they find him with Pulaski in his hideout, they are shocked when they learn that Moriarty is aware of the holodeck program being a simulation, and is able to access the holodeck computer, showing them a sketch of the Enterprise he has drawn based on the computer's description. Data and Geordi leave the holodeck to alert the captain, and Geordi realizes that when he asked the computer to create the program he had asked for an adversary who could defeat Data, not Sherlock Holmes; as a result, the computer gave the holodeck character, Professor Moriarty, the intelligence and cunning needed to challenge Data, plus the ability to access the ship's computer. When Moriarty gains access to ship stabilizer controls, Data returns to the holodeck with Captain Picard.

Picard meets Moriarty, who demonstrates that he has evolved beyond his original programming and asks to continue to exist in the real world. Picard tells Moriarty that this would not be possible; instead, he saves the program and tells Moriarty that if they ever discover a way to convert holodeck matter into a permanent form they will bring him back. Picard discontinues the program and the USS Victory arrives, with La Forge preparing to present a model of the historic HMS Victory.

"Elementary, Dear Data" was written by Brian Alan Lane and directed by Rob Bowman.

This episode contains elements from and references to the Sherlock Holmes short stories "A Scandal in Bohemia", "The Red-Headed League", "The Adventure of the Speckled Band", and "The Adventure of the Bruce-Partington Plans", as well as the Holmes novel The Valley of Fear. Furthermore, Moriarty's creation being a result of Geordi La Forge requesting an opponent capable of defeating Data references Arthur Conan Doyle's creation of the same character for the short story The Final Problem – specifically, as an opponent capable of defeating Sherlock Holmes who, at the time, Doyle wanted to kill off.