At the bar, Quark and Odo bicker expositionally about this week’s guest stars, one of whom is killed by another in the very next scene.
The victim’s twin brother swears vengeance against the shooter Croden. Odo suspects that Quark arranged for Croden to interrupt a surreptitious business deal and steal the macguffin, but just when the mystery gets going, the A plot drops: Croden casually compares Odo to the other “changelings” he’s met.
Though fully aware that the sympathetic rogue Croden is probably lying, Odo is nevertheless intrigued at the chance to meet other shape-shifters. Croden’s story gains some credibilty from his locket, a stone that morphs into a geometric shape. Bashir reports it “might qualify as a distant cousin” of Odo.
The B-plot develops the criminal investigation, which includes Sisko doing diplomacy with Croden’s home planet (where Croden is already considered a criminal).
Odo is tasked with taking Croden back to his home planet. Some sfx shots that still hold up very well (were they still using models at this point?) feature a runabout hiding behind a larger ship, and being stalked and attacked by a much more powerful vessel.
Even though Sisko knows Odo will be targeted, he doesn’t think to send a qualified weapons officer along. But guess who has valuable tactical training? The prisoner, who offers to help. He takes them into a convenient nebula — the very nebula where he says he stumbled across a changeling colony.
To his credit, Odo has had enough, but by then they’ve already landed on an asteroid and they’ve entered a convenient cave (featuring lighting, gravity, and a breathable atmosphere) — the very cave that Croden says leads to the changeling colony.
Less than a minute after we learn Croden’s big secret, there’s a conveniently timed cave-in ex machina, which provides the fugitive with a perfect opportunity to escape.
It’s low-hanging tropes all the way down, including the plot contrivance particles hanging out in the nebula; but the character development is… pardon the Changeling pun… “solid.” Croden manages to stir the grumpy loner Odo’s longing to connect with others like him. When Rom rejoices that it looks like Odo will be killed, Quark lashes out at him. These character acs will continue to develop through the rest of the series.
When we first met Odo, he was able to morph into goo in order to avoid something thrown at his head. In this episode, even though he seems to be aware of his surroundings even while disguised as a glass on a tray, he’s not able to use his shape-shifting ability to avoid being injured by falling rocks. Injured.. how? He’s apparently an amalgam of crystalline and biological matter without any definite internal organs, yet when he’s knocked out, he retains solid form (though we’ve been told his “natural state,” to which we might expect him to return when unconscious, is goo] which is supposed to require some kind of effort), and when he wakes up he complains of a “headache.”
Was he faking his injury to see what Croden would do? (Probably not, because delaying their escape would have put an innocent third party in further danger, which is off-brand for Odo, even this early in the series.)
I’ll give it a pass, though. After all, when we first met Mr. Spock in the original Star Trek pilot “The Cage,” he shares a chuckle with Captain Pike while observing the strange sounds made by alien leaves. Obviously the writers hadn’t yet worked out Odo’s biology.