Undeveloped Star Trek: Deep Space Nine episodes

Numerous undeveloped Star Trek episodes were written for Star Trek: Deep Space Nine. These stories were submitted or developed for production, but for various reasons never aired.

Day at Quark's
Ronald D. Moore pitched an episode that would have revolved around an entire day at Quark's.

Dysfunctional
Ezri secretly arranges to have the Dax symbiont removed. (SFX: The Essential Guide to Deep Space Nine)

Klingon Hell
Ron Moore's original concept for was for Worf and the crew of the Rotarran to enter Gre'thor. (Star Trek: Deep Space Nine Companion). While ultimately unused in DS9, this concept was later developed into.

Nausicaan episode
In 1997, Ira Steven Behr commented to Star Trek Monthly, "You know the Nausicaans? They'll be back, and we'll do a show about them being an enemy for an episode". ("On Things Past, Present and Future", Star Trek Monthly, issue 30)

Sito Jaxa return
One story considered by the writing staff concerned the return of Sito Jaxa from. The pitch had Sito being imprisoned under inhumane conditions and suffering from post-traumatic stress disorder. Robert Hewitt Wolfe developed the story for some time. Feeling that there was insufficient explanation of Sito's condition, he had Sito killing her cellmate, whom she'd become close to. (Star Trek: Deep Space Nine Companion, p. 326) According to Ronald D. Moore, "We talked about this for quite awhile, but then decided that bringing Sito back would rob 'Lower Decks' of a great ending."

While unused, Wolfe later incorporated elements of the story into. He commented, "I took the end of the Sito story and threw away the rest." (Star Trek: Deep Space Nine Companion, p. 326)

Thomas Riker return
After, Jonathan Frakes lobbied the producers to bring back Thomas Riker for a sequel episode. Frakes noted, "I keep thinking Tom is coming back...don't you think it makes sense for them to send Kira over there to free Thomas? It's a no-brainer." Frakes, however, received no definite indication from the producers. (Star Trek: Deep Space Nine Companion, p. 191)

The Star Trek: Deep Space Nine Companion (pp. 191-192) states that in the fourth season pitch letter sent to freelance writers, Thomas Riker was listed as a subject that the producers were not interested on hearing about. However, the authors note that this could have meant that the producers were already working on such a story. Several comments from Ronald D. Moore indicate that the writers did seriously consider the possibility. In the book, Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages, Moore commented that "We'll probably see a return-of-Tom Riker episode. What's nice is he's not really a part of Next Generation, so he's ours, and we can do what we want with him and not worry about what the movies do with Will Riker." (p. 87). Likewise, in an online chat with fans, Moore noted that, "Tom Riker may or may not get rescued at some point."

In an interview with Jonathan Frakes provided with the TNG Season 6 DVD box set, he states that he had approached Moore regarding a Thomas Riker episode involving Damar's rebellion. However, the character never appeared again.

Musical Episode
Ronald D. Moore had advocated doing a musical episode. "Oh, and I was agitating for a musical, man. On record, I wanted to do a musical version of Trek well before Buffy or Chicago Hope. I wanted to do a musical episode, and nobody would f***in' do it." When the interview spoke of how this was accomplished on Buffy the Vampire Slayer, Moore responded:  ''"Yeah, that's all we needed to do. There's just some tech virus that infects the crew and they can only communicate in song, you know? And just do it! And have a ball. That was part of the struggle on Next Gen, too, was to just have fun. "Can we just do a laugh for an episode? Where it's not so serious, where we [don't] have to put the ship in jeopardy every week, where someone's life hangs in the balance. Let's just do a comedy episode." And that was a real – they fought against it and fought against it and fought against it."''

Quorum
Jack Treviño and Toni Marberry sold three stories to Deep Space Nine, but only two were filmed. The third story, sold about a year after the team sold and, was called "Quorum". However, it went unproduced.