DS9 again returns to the political intrigue territory it knows so well when William Riker (Jonathan Frakes) visits the station and steals the Defiant, then begins charging through Cardassian space with the deadly weapon and not exactly diplomatic intentions.
Not actually Will Riker, but Thomas Riker, a duplicate of the Enterprise first officer created in a transporter mishap nine years ago and discovered two years ago in TNG's episode "Second Chances." Thomas impersonates his doppelganger to gain Kira's trust and a tour of the Defiant. After stunning her with a phaser, he beams a skeleton Maquis crew aboard the warship then promptly warps away from DS9.
Having Frakes cross over to DS9 is, of course, fun, but what makes this episode work in the long run is its compellingly intricate plot and another pairing up of Sisko and Dukat.
Sisko travels to Cardassia Prime to help Dukat hunt down the renegade Defiant and prevent an interstellar incident. Meanwhile, Riker reveals his intentions to the helpless Kira: To check out whether a group of renegade Cardassians is building a secret fleet in the Orious System.
Again, the enigmatic Obsidian Order (well-utilized in "Second Skin") comes into play, this time in the form of Korinas (Tricia O'Neil), who observes the tracking process with Sisko and Dukat. Korinas has the closest thing to an evil grin that DS9 has yet dare use, and O'Neil's performance is chillingly effective. As the search draws nearer to the Orious System, she becomes uneasy, quickly stating that no ship may enter the Orious System or the Obsidian Order will destroy it—including a ship of the Central Command.
There are a number of intriguing scenes at the tracking facility as the uninformed Dukat slowly begins to suspect the Obsidian Order may be plotting behind the back of the Central Command. Like in "The Maquis," Sisko and Dukat find themselves working together, albeit under different agendas. The real payoff in "Defiant" is how the sequence of events brings both to realize where the real threat lies—not with Riker in the Defiant, but with the Order's suspected use of forbidden power, who has apparently been building illegal military equipment.
This leads Dukat to strike a deal: In exchange for the sensor logs the Defiant has obtained on the mysterious Orious System, the Cardassians will release the Defiant and its crew, less Riker who must be sentenced to death. Sisko works with Dukat to reduce the sentence to life imprisonment.
This is a fine script by Ron Moore, with the most interesting plot manipulations so far this season. Cliff Bole's direction is also nicely paced, balancing a number of character scenes between Dukat and Sisko with the suspenseful Hunt-for-Red-October-inspired plot. While both Sisko and Dukat stay perfectly in character, there's a personal respect for each other that these two begin to discover—something that surfaced in "Maquis" which also works well here. The writers also manage to work in a tad of the inner-character conflict of the duplicate Riker—a little bit of identity crisis that wasn't sufficiently addressed in "Second Chances." And best of all, this whole Obsidian Order thing just screams of future development, possibly a Cardassian revolution or worse.
Indeed, political intrigue is what DS9 knows best.