Like Star Trek: The Next Generation before it, Season 3 is where DS9 upped the ante in terms of story arcs, character development, backstory and just plain overall crunchy goodness.  For part of this season DS9 was the only Trek show on air and the producers used their time wisely. Season 3 put to good use the show's ever-expanding story canvas by featuring revealing two-parters, exposing Ferengi cultural values, questioning medical ethics, returning to the mirror universe, and examining former Bajoran resistance leaders. Odo, for one, develops tremendously during this season with more revelations about his people and his desire to join with them, his killing of another changeling, and of course his confession of love to "Kira." There's more, of course, but Season 3 could be seen as the year the show seemed to take off in new directions for Star Trek and the year that Deep Space Nine became even greater than it already was.

Here, in no particular order and with apologies to the other great episodes not listed, is a top selection from the Junior year of Deep Space Nine.

The Search, Parts I and II
By now we know there may be a serious and deadly threat emanating from the Gamma Quadrant.  To that end, Starfleet has built a prototype starship whose technology stems from research on how to combat the Borg. From this emerges the Defiant, a ship that will figure in the story of DS9 from here to the end of the show. The episode touches base with Odo's race of shapeshifters, the Jem'Hadar, the Defiant, the Vorta and the Dominion. A table setter, "The Search" features many of the elements that will come to define the show from here on.

Defiant
The creation of Thomas Riker, the result of a transporter accident as seen in the Star Trek: The Next Generation episode "Second Chances," always had larger implications: a man with Will Riker's memories, but with some serious differences. For one, Thomas has taken up with the Maquis and was looking to help them gain an edge in their skirmishes with the Cardassians. And what better way than to steal the formidable Defiant? Well, the best-laid plans of Maquis and men don't always play out and Riker is caught and sentenced to life in a Cardassian labor camp. The person who was duped by the faux Will Riker, Kira Nerys, is saddened by the fate of this man who both impressed her and shocked her with his brazen theft of a vital piece of Starfleet equipment. Of course the question remains: is Thomas Riker still confined to that labor camp, or has he cleverly found his way out to pursue a different destiny ...?

Past Tense, Parts I and II
The best way to learn about history isn't to read about it in a book, but to live it. And that is exactly what several of the crew of DS9 do in this trip in the way-back machine to Earth, circa 2024. It's a time of unrest in our world and the undesirables of this period are put into ghetto areas where they can't bother the rest of society. When Sisko, Dax and Bashir materialize on Earth, they land smack dab in the middle of some unrest. In a strange twist of fate, and to ensure that things work on a temporal/historical level, Sisko finds himself having to fulfill the role of the suddenly dead hero of the day, Gabriel Bell. Meanwhile, Kira and O'Brien are trying desperately to find their time-bending comrades and have some interesting encounters with people of different eras on the exact same San Francisco street. This nightmare scenario of Earth society in the not-too-distant future is one of the things that makes Star Trek so compelling.

Life Support
In another classic Trek storyline, Dr. Bashir faces an ethical conundrum that tests his skills as a physician and professional surgeon, and a medical counselor. This is one of those doctor-patient-ethics issues and Bashir is put in a very difficult position to keep Bajoran spiritual leader Vedek Bareil alive following a shuttle crash, as he's needed for some important negotiations to take place between the Bajorans and the Cardassians. Kai Winn, lacking confidence to go it alone, needs Bareil. But, in this heroic tale of sacrifice, Bareil opts to help advise in the negotiations at the expense of his own life. He could have been put in stasis and perhaps saved. Did we mention that he was also Kira's main squeeze at this point? In a nice twist, this story of death and sacrifice is countered with a B-story of young Jake Sisko's love interest which tests his friendship with Nog.

Prophet Motive
When Grand Nagus Zek returns to DS9, he's convinced that the ways of the Ferengi are based too much on greed and they must move beyond this to become truly successful. Quark is horrified upon hearing this news and facing sobering new rules of acquisition such as: "If they want their money back ... give it to them." He and Rom are determined to find out what happened to Zek. The brothers Ferengi find out that Zek was transformed by the wormhole aliens into a kinder, gentler version of his race. Well, not content with the changes that face all Ferengi, Quark journeys to the wormhole, chastises the Prophets for judging his society's value system, and strikes a bargain saying his people will never bother them again as long as they restore Zek to his natural, greedy ways. Once again, for better or for worse, the Ferengi are used for light relief. But, as usual, there are valuable lessons learned at the same time.

Through the Looking Glass
The mirror universe may not be everyone's cup of tea, but what it does give us is the same characters, only in a different light; a "what if" scenario that is fun, engaging, sexy and sometimes downright dangerous. This episode even threw in a character from another Star Trek show – Tuvok from Voyager! What a mirror universe episode offers is a perspective gained not from the old stand-by of time travel, but of same time, same place, just different circumstances. Once again, along similar lines of the above-mentioned "Past Tense," Sisko is called in to pretend to be someone he isn't – himself!

The Die is Cast
With the return of Enabran Tain from the recent "Improbable Cause," the increasingly complex saga that is Deep Space Nine continues apace. When a fleet of Romulan and Cardassian warships appear at DS9, you just know things cannot be good. Add to the mix a surreptitious journey to the Gamma Quadrant, an encounter with the Jem'Hadar, the near death of Odo – who's being pumped for valuable information about his people – and you have a story so layered with potential future storylines that this may be one of the most aptly named episodes to date.

Shakaar
No, we didn't pick this one because of Miles O'Brien's run of good fortune at the dartboard, but more for the continuing addition of background to the Major Kira story. A story of Bajoran loyalty, history and friendship, "Shakaar," named after the former resistance fighting partner of Kira, deals with Bajorans and how they deal with other Bajorans. As the overall arc of DS9 heats up, this episode brings it back down to Bajor and introduces someone we, and Kira, would see more of in the future, Shakaar Edon.

The Adversary
Sisko gets promoted to captain! Well, we knew changes were afoot when Sisko started adding the facial hair that would presage his total transformation to a goateed and shaved-head captain. But that's all beside the point. "The Adversary," the season finale, is where we see first-hand the dangers of other changelings and the threat they pose. When the Founders fake information about a Tzenkethi coup in order to get the Federation involved and to destabilize the Quadrant, it is revealed to what depths the Founders will go to foment war, including impersonation of Starfleet officers. But when Odo inadvertently kills another changeling, his life is marked for change.