Before we get started with our next Trek series, some background...
One of the biggest complaints about TNG was that the crew were all buddies--there was little or no disagreement or hostility among them. So, the suits at Paramount did what suits do--overcompensate the next time. The new series, Deep Space Nine, would have a crew that HATED each other. Roddenberry would never have allowed this--he thought that hate would be eradicated by the Trek future--but he passed way in 1991.
The series began in 1993, in the middle of TNG Season 6. The concept--just as TOS was about the US (Starfleet) vs. the Russkies (Klingons), and TNG was about Perestroika (Starfleet and Klingons are now buddies), DS9 is about the Arab/Israeli conflict in SPACE! The Bajorans (Israelis), introduced on TNG via Ro Laren, are a religious people brought to war by the Cardassians (Arabs), already established as bad guys on TNG. A tentative truce has been found, and the Federation wants to keep it (and the Bajorans) alive. Cardassian space station Terek Nor, orbiting Bajor, is renamed Deep Space Nine, run officially by the Bajorans with "assistance" by Starfleet.
New Captain (actually Commander) Benjamin Sisko, played by Avery Brooks, has his own baggage. His wife was killed during the Borg battle at Wolf 359 (TNG's The Best of Both Worlds), and has a son Jake (Cirroc Lofton) to worry about. Major Kira Nerys (Nana Visitor) is the Bajoran attache and his "Number One". She has a chip on her shoulder the size of an asteroid, since she was a combatant in the war, and now has to work with with the Cardassians. Chief Miles O'Brien (Colm Meaney), fresh from TNG, comes over as Operations Chief, along with his wife Keiko (Rosalind Chao) and baby daughter Molly. Sisko brings in old friend Dax (Terry Farrell), a Trill (a "joined species" introduced on TNG), with old being relative--the previous host was an old man, but is now a beautiful young woman. Sisko refers to her as "old man" throughout the series. Dr. Julian Bashir (Alexander Siddig--his name during the series was Siddig El Fadil, but changed it post-9/11), a young but brilliant physician, comes on as a medical officer looking for adventure. The existing security officer Odo (Rene Auberjonois) stayed aboard--a shapeshifter with a mysterious past--along with Quark (Armin Shimerman), a Ferengi bar owner and Odo's nemesis.
So, you have a lot of people with various conflicts and distrusts--the show begins and continues with a LOT of tension.
You've also got a space station instead of a ship, so trouble generally comes to them, rather than the other way around. When this was first announced as a series, I hoped it would be an anthology series--people come onto the station, we follow their story for an episode or two, and then we move on. I still think that would be a great Trek series--you could have a medical drama one week, a love story the next, a crime procedural, a Starfleet Academy story--you name it.
We're got seven seasons to cover, so we'll start next time. Star Trek: Deep Space Nine (and all the Trek series) is available on Netflix.