the story: A follow-up to the classic episode "Mirror, Mirror."
what it's all about: This is the level of confidence, and audacity, the second season of Deep Space Nine had introduced to the series. Well before the prequel nature of Enterprise made it easier to provide follow-ups to previous episodes of the franchise, let alone sequels to episodes of the original series, "Crossover" began a whole tradition in Deep Space Nine, a whole series of episodes set in the so-called Mirror Universe.
What started with "Blood Oath" a few episodes earlier, in which three actors who portrayed Klingons in the original series returned," culminates with "Crossover." The curious thing about the series, which is a problem that persists today, is that fans question its faithfulness to the Star Trek tradition, because it departs to dramatically in tone. And yet episodes like this easily evoke not only its fondness for that tradition, but its faithfulness. In "Mirror, Mirror," Kirk is forced to confront a reality in which the moral decisions he has long taken for granted from those around him are not a given. Yet, it's him who sets a new standard. In essence, he's in the same predicament as he's always in. Yet in "Crossover," it's the Mirror Sisko who makes the difference, despite the presence of Bashir and Kira from the standard reality. He'd been as corrupt as anyone before they showed up, but he suddenly discovers his moral compass pointed in the right direction because of their influence. Where we only suspect Mirror Spock has indeed taken Kirk's parting message to heart, "Crossover" is an active demonstration of all that classic Star Trek hope for the future, even if it seems anything but.
It's not so much that "Crossover" provides a follow-up to "Mirror, Mirror," but that it proves things aren't so easy to fix as Kirk could sometimes suggest. More than a century later, his actions in the Mirror Universe have drastically changed things, but not as he imagined they would. Humans have become an embattled species. Sure, the whole thing allows the series to present familiar characters in unfamiliar roles (Kira becomes doubly iconic thanks to this initial appearance of her Intendant counterpart, the most sensational and successful variant, although Odo's one-off take is pretty darn shocking, too), but it's a whole exercise in demonstrating what Deep Space Nine would be like moving forward, what the season had hoped to accomplish all along but hadn't quite managed to nail until the last few episodes. Basically "Crossover" is a massive tease for the rest of the series, its confidence now unshakeable.
You can watch "Crossover" on its own, ignore all its follow-ups, and still feel its impact. If you somehow thought Enterprise's two-part "In a Mirror, Darkly" was the only "Mirror, Mirror" spin-off worth remembering, think again.
- franchise - Again, it's a sequel to "Mirror, Mirror."
- series - And yet it's completely relevant to Deep Space Nine itself.
- character - The debut of Intendant Kira.
- essential - A classic sequel to a classic.
Andrew Robinson (Garak)