Bashir and Garak are having their typical lunch together on the promenade, and Bashir is a tad grumpy. As Garak finds out, the good doctor is turning the dreaded 3-0. Garak doesn't see what the problem is, since Cardassian culture sees growing old as a sign of power. Bashir tells Garak that he simply doesn't like being reminded that he is getting older.
In the middle of their discussion, a clearly nervous Quark approaches with a menacing Lethean named Altovar. He's looking to purchase some bio-mimetic gel... which is a restricted substance that's banned from purchase. When Bashir informs him of this, Altovar storms off.
Returning to sick-bay, Bashir finds Altovar ransacking his medical supplies. When Bashir tries to stop him, he gets a psychic shock to the noggin and passes out on the spot.
Waking up, Bashir discovers that his whole office is on the fritz and his temples have suddenly started to grey. Venturing out into the promenade to see what's going on, the doctor finds the station void of life. He can't contact anyone, and the computer appears to be down. Wandering into Quark's, he discovers the barkeep cowering behind his counter. A mysterious figure in the shadows is trashing the place. Quark bolts from the scene, leaving Bashir alone again.
After getting some chairs thrown at him from the darkness, Bashir leaves the bar and heads for the security office. He finds Garak, who isn't able to provide much more information about what's going on. The Cardassian notices Bashir's hair is even grayer than before. To top it off, Bashir is hearing faint voices in his head.
Heading down a random corridor, the lights begin to go out one by one. Bashir breaks for the nearest turbolift, and encounters an angry Altovar, but the doctor escapes courtesy of a swift kick to the face.
Things seem on the up as Bashir finds Dax, Kira, O'Brien and Odo huddled in the wardroom, but they're all acting very out of character. O'Brien is cowardly, Odo is more paranoid than usual, Dax is itching to fight an enemy, and Kira is acting especially sharp. They note that Bashir appears to have aged 30 years, and they're not at all pleased to learn that he's hearing voices. In spite of it all, they formulate a plan to get communications up.
When O'Brien completes the repair, they pick up something. It sounds like a conversation between Dax and Sisko, talking about how Bashir is comatose and has hours to live. Bashir realizes that Altovar's attack put him in a coma, and everything he's experiencing is in his head. If he doesn't figure out a way to wake up, he'll soon die.
Bashir's crew are understandably incredulous about being figments of Bashir's imagination. He deduces that each of them represent an aspect of his personality. And just like that, Altovar appears out of nowhere and drags Dax off. Bashir goes to bang on the door... and finds himself playing tennis on the promenade with Garak. In his 80s by now, Bashir heads off with Garak to try and fix his brain by fixing the station.
Bashir happens upon Sisko, who is treating injured patients, representing Bashir's professionalism. Sisko agrees to help Bashir, but barely takes a step before Altovar drags him away through a wall. Kira, Odo, O'Brien and Quark are all dispatched as well, leaving Bashir with no allies... except Garak. After breaking his hip, Bashir convinces the Cardassian to help him to Ops, where Garak throws him a surprise birthday party.
Bashir brushes aside the festivities and tries to restart the computer, but the consoles are filled with tennis balls, much to Garak's amusement. At his wit's end, Bashir finally questions Garak on what he represents and discovers that he's actually Altovar in disguise. Altovar confronts Bashir on his weaknesses, reminding him that he abandoned his dream of being a tennis player to appease his parents and has never been able to seal the deal with Dax. He also accuses Bashir of purposefully botching that one question on his final exam so that he wouldn't feel the pressure of being first in his class.
Bashir counters that he loves being a doctor, he treasures his friendship with Dax, and he would have chosen to serve on DS9 even if he had graduated first, so nothing Altovar said really matters. He completes his repairs to the computer and vaporizes Altovar.
Bashir awakens in sick bay none of the worse for wear. In his next lunch with Garak, he announces that after aging so rapidly in his mind, turning 30 is not so bad after all.
- And You Were There: Members of DS9 appear as various aspects of Bashir's personality, though it turns out that Garak is actually Altovar in disguise. The real Garak's reaction to being cast as the villain by Bashir's subconscious is humorously typical of him.Garak: To think, after all this time, all our lunches together... you still don't trust me. There's hope for you yet, Doctor.
- Battle in the Center of the Mind: Bashir works out how to turn the situation against his enemy, by moving to Sickbay, which is his domain.
- Bottle Episode: Bashir's mind conveniently looks just like the existing Deep Space Nine set and cast, with only one new alien character to design.
- Continuity Nod: Altovar accuses Bashir of intentionally making up the whole 'confused the preganglionic fiber for a postganglionic nerve' so he would be second rather than first in his class. Writer Robert Hewitt Wolfe included this line because his wife, who was studying to become a vet, had repeatedly pointed out that no one in the medical field would mix them up.
- Dark World: The entire space station during Bashir's coma is this.
- Deliberate Values Dissonance: In Cardassian mystery novels, the suspects are always guilty. According to Garak, the challenge is determining who's guilty of what.
- Dream Apocalypse: Brought up briefly when O'Brien asks Bashir, "If you wake up, what happens to us?" Ultimately somewhat moot, though, as Altovar has already killed all the dream characters by the time Bashir awakens.
- Foreshadowing: Garak is the only "crewmember" to readily accept the idea that he isn't real and is just a representation of an aspect of Bashir's mind, and reminds him of this fact a few times. This is because he's not Garak, he's Altovar in disguise.
- Happy Birthday to You!: Played straight as the woman waiting in Ops sings this to Bashir upon entering.
- The Hero's Birthday: It's Bashir's 30th, and he's not happy about it.
- I'm Melting!: Odo dissolves in a puddle while Bashir is trying to get to Ops.
- Journey to the Center of the Mind: And a screwy journey at that.
- Milestone Birthday Angst: Bashir doesn't mind birthdays in general, but he's not thrilled about reaching the big 3-0.
- Out-of-Character Alert: Bashir starts to realize something's wrong when he notices how oddly the four people he's with are behaving. O'Brien has become unusually pessimistic, Dax is determined to hunt down the Lethean, Odo has become paranoid — accusing O'Brien of all people of being in league with the villain — and Kira is overly aggressive and impatient. This is because none of them are real, but aspects of Bashir's personality.
- Paper Tiger: Altovar is an unstoppable juggernaut ripping apart the station and killing its crew at will. Real Altovar bumbles into an alarm and is caught within seconds.
- Rapid Aging: Bashir appears to go through this, though it turns out that it's the weakening of his life signs that's causing the aging inside his mind.
- "The Reason You Suck" Speech: Altovar gives one to Bashir at the climax, accusing him of giving up every shot he's had at getting what he wants, namely his chance to be a pro tennis player, his chance to be valedictorian of his class, and his chance at a relationship with Jadzia.
- Sadist: Altovar takes obvious pleasure in telling Bashir he's going to make him watch as he slowly destroys him from the inside, only allowing him to die when there's nothing left of him but a withered shell. And considering he did all this to Bashir on purpose, presumably the real Altovar is one as well.
- Shock and Awe: Altovar gives Bashir a telepathic mental shock that puts him in a coma.
- Shut Up, Hannibal!: Bashir responds to Altovar's "The Reason You Suck" Speech by asserting that he doesn't regret getting what he got instead of them (his career as a doctor, the DS9 posting, Jadzia's friendship) and he's entirely happy with his life as it is.
- Trash the Set: Quark's Bar when Bashir first looks through the station to find out what's gone wrong. Later on, as Bashir finds out that the station is really his mind, the bar appears to be reset to its original appearance, though most of it is still unlit.
- Unobtanium: Bio-mimetic gel, a substance so volatile (and useful) that people are willing to kill for milliliters of the stuff. Later episodes will establish that among its uses are genetic modification and extremely powerful explosives.