Star Trek: 15 Best Holodeck Moments

After settling the legal rights issues with the estate of Sir Arthur Conan Doyle, the producers were free to make another story featuring Professor Moriarty. The episode hangs a lampshade on this delay, revealing that Moriarty was aware of the time passing.

The episode is a minefield of trying to remember which is the real world and which isn't. The clue is that from the moment Picard, Data and Barclay enter the holodeck, until Moriarty calls them from the shuttle, there are no exterior shots of the Enterprise. Troi is wearing a different style uniform as well.

The episode came about when the crew were trying to break a story that involved the holodeck, and Moriarty was brought up. The initial feud between Doyle's estate and Paramount had actually come from Young Sherlock Holmes, rather than their episode. Jeri Taylor found them quite reasonable when she approached them about this story.

There was some debate as to whether or not to use Barclay in the episode. They wanted to have a character who was unaware of what had happened before, and so he was picked, yet once Moriarty takes control this removes the need for this character's point of view. However, as René Echevarria stated - only Barclay could make the last line of the episode work.

The episode also contains the last reference to Dr. Pulaski, though not by name, until Endgame. Moriarty recalls holding her hostage. Such is her legacy in the Next Generation.