Kira and Odo are on their way back to DS9 from a colony. Kira emits some clumsy exposition before observing that Odo seems miffed about something. He's annoyed she didn't consult him on turning down an invitation to a dinner he didn't want to go to. Did I miss the episode they got married in? Then they detect what may be a Marquis ship and pursue it into the badlands.
Meanwhile, O'Brien is being Sisko's secretary. Nog presents Sisko with a gift of latinum - he's undergone the Ferengi ceremony to become a man, and wants to purchase an apprenticeship under Sisko. Sisko points out that to join Star Fleet, he has to attend the academy, and as a non-Federation citizen, he needs a letter of recommendation from a senior Star Fleet officer. Nog happily believes Sisko will write him one. Yet another B plot which is not even mentioned on the startrek.com page. AKA how to know when your b plots suck.
Kira gets her foot stuck in a crystal while ambling about caves on the moon they tracked the Marquis ship to. Odo observes that the crystal appears to be growing. This is obviously the Trek version of the Genesis of the Daleks clam. Odo does the sensible thing and hits it with a rock. This isn't helpful, so Kira has a go with her phaser. This has the opposite effect to that desired. Odo sets out back to the Runabout so he can transport her out.
Back on t' station, Rom and Nog are trying to fix the replicator in Quark's bar. Jake thinks Nog was joking about wanting to join Star Fleet, but Nog is adamant he wants to.
Odo attempts to beam Kira out, but there's too much interference. He launches a probe to broadcast a distress call in DS9 - the computer reports the signal should reach DS9 in around two days. Sighing, he returns to Kira, who's just had an altercation with the Marquis fellow they tracked there.
Bashir tells Sisko that one of the ensigns is having a baby. The switch is that the ensign is male and an amphibian. Yay. Sisko tells Nog he's not Star Fleet material. After Nog pleads, Sisko decides to assign him to inventory the equipment in cargo bay 12.
Kira is now up to her waist in crystal. Odo relates a story about how some Nauusicans used sound resonance to break some crystals, and sets off back to the runabout to get some equipment to set up something.
Dax assigns an unimpressed Nog to the cargo bay.
Odo's set up his resonator, and mentions he's got an appointment to go kayaking with O'Brien in the holosuites, much to Kira's amusement. Then there are more tremors and rocks fall.
Nog's completed his inventory successfully. Yay, Nog!
Odo's resonance device has failed to find the correct frequency. She asks him to relate the story of how he got his name, and it turns out it's Cardassian for "nothing". As they realise there's nothing more they can do, Kira orders Odo to take the runabout and go. Odo says he's resigning his commission rather than leave. She demands he leaves, and he admits he won't because he's in love with her. Awwwwwwwwww.
Sisko tells Nog that he's still not academy material. Nog insists, and admits he wants to get into Star Fleet because he doesn't want to end up like his dad.
Odo realises that if the Marquis guy was standing where Kira said, she was blocking where the phaser hit the wall. Confronting her, Kira morphs into Female Shapeshifter - she was the fugitive they'd been after, fishing for information about why he's chosen to live with the solids. After she beams out, Odo goes and rescues the real Kira.
Meanwhile, Rom gives Nog his blessing to enter Star Fleet.