This episode of "O'Brien Must Suffer" opens with a haggard man with long gray hair with his back to the camera, drawing a pattern in the sand. A wave of energy passes through and erases the pattern, and he starts drawing again. The camera angle changes, and we see that it's Chief O'Brien. His drawing is interrupted by a pair of guards entering the room, telling him that he has exceeded the necessary incarceration and must be released. They throw him out of his cell...
...and the scene changes to show him strapped to a table. O'Brien is incredulous when he sees Major Kira, looking the same as she did when he entered the prison, 20 years ago. The guards explain that he's only been in custody for a few hours, that his incarceration has been all in his mind, and that none of what just happened to him was real. "It's real to me, Major," he intones gravely. "It's real to me."
Captain Sisko explains the situation to O'Brien's wife, Keiko: O'Brien was on a team that visited Argrathi, but when he asked too many questions about Argrathi technology, the paranoid local authorities arrested him for espionage, and before his fellow Starfleet officers had even realized that he had gone missing, O'Brien had in short order been subjected to a very swift and likely unfair trial and found guilty. The Argrathi does not punish criminals with actual prison, however, but rather by implanting memories of being harshly incarcerated into their mind, and O'Brien was subjected to the said 20 years of this in the few hours it took Star Fleet to negotiate his release. Keiko asks if the memories are removable, and while Sisko reports that the Argrathi say it's impossible, Sisko reassures her that Dr. Bashir will try. Bashir interviews O'Brien on what he remembers. O'Brien had a cellmate, a man named Ee'char who had already been in the prison for six cycles prior to O'Brien's arrival, but he tells Bashir he was alone. After finishing his assessment, Bashir explains to Keiko that the memories O'Brien received aren't implanted false memories, but that O'Brien actually experienced everything that happened at an accelerated rate and so there isn't anything he can do without wiping everything else from his memory entirely. For a brief moment as he's being reunited with Keiko, he sees her as Ee'char.
O'Brien has a hard time readjusting: he unconsciously saves a portion of his dinner for later, a habit he picked up as a result of the rarity of the guards bringing food. Keiko finds him sleeping on the floor. He sees Ee'char walking through the station while playing darts in Quark's Bar. He's been temporarily demoted until he can get his technical faculties back. When Bashir goes to visit him, we find that he hasn't been seeing the counselor he's supposed to have been seeing three times a week. O'Brien doesn't want to talk about it, he just wants to forget what happened to him and becomes argumentative when Bashir presses the issue.
In a flashback, O'Brien gets into an argument with Ee'char, where he appears to be losing his sanity. After threatening Quark with violence when he doesn't deliver O'Brien's synthale as quickly as he'd like, he has another vision of Ee'char.
Sisko calls O'Brien into his office. Because of the argument with Bashir, the incident with Quark, and his continued refusal to see the counselor, he is relieved of duty and forced to see the counselor daily. O'Brien storms into Bashir's office. As Ee'char appears again, Bashir urges O'Brien to listen to him and accept his help. O'Brien doesn't want Bashir's help; he just wants to be left alone. As he walks through the promenade, the vision of Ee'char says, "You know sooner or later you'll have to tell someone about me." When he gets back to his quarters, Keiko tries to reason with him. His daughter Molly keeps trying to show O'Brien the drawing she made, which sets O'Brien off and makes him nearly hit her before he's stopped by Keiko. O'Brien is deeply shocked at what he nearly did to his daughter, and quickly leaves the apartment.
O'Brien hides in the cargo bay, where he is overcome with rage and smashes a container before opening a weapons locker and pointing a phaser at his neck. Bashir comes in and begins talking O'Brien down. O'Brien rationalizes that he's about to kill himself to protect Keiko and Molly and everyone else on the station from the man that he's become after 20 years of prison. Bashir reassures him that O'Brien is still a good, decent man, and O'Brien begins to open up to Bashir about Ee'char.
They were cellmates up until a week before O'Brien was released. The guards had gone longer without giving them food than they ever had before, and Ee'char mused that the guards might have forgotten about them. Later that night, O'Brien wakes to discover that Ee'char had been keeping a secret stash of food from O'Brien. In a rage, O'Brien attacks him and ends up killing him in the ensuing fight — only to find that the food has been divided into two portions, clearly indicating that Ee'char had meant for it to be for both of them. Compounding his guilt, the guards began feeding him again the next day. He had killed his friend for nothing.
Bashir reassures him:
Bashir manages to get the phaser away from O'Brien as Ee'char fades away after gently smiling and telling O'Brien to "Be well."
We then see Bashir discussing the medicine he's prescribed O'Brien. It'll combat the hallucinations and the depression, but not the guilt. That will only take time. He returns to his quarters where he is warmly greeted by Molly.
- Butt-Monkey: It's an "O'Brien Must Suffer" episode on steroids, as the Argrathi squeeze twenty years of suffering into just a few hours.
- Deconstruction: This episode has a similar idea as in the TNG episode The Inner Light, but here we actually see how difficult it would be to adjust to your former life after having spent decades inside a simulation. Of course, there was a great difference in what the simulation contained; Picard was made to participate in a exploration of the waning years of a dying alien culture and saw them display their inner strength and optimism as they refused to succumb to despair but held out hope to the end, even in the face of certain oblivion, O'Brien was just essentially subjected to slow-working psychological torture. Though like Picard in The Inner Light, O'Brien's still back to his normal self by the next episode.
- Driven to Suicide: To the brink, anyway, before Bashir arrives in time to talk O'Brien down.
- The Ghost: Counselor Telnorri, who is apparently Deep Space 9's resident psychologist, never appears.
- Go Out with a Smile: "Be well, Miles."
- Helpful Hallucination: Rather than blaming Miles for "killing" him, the apparition of Ee'char that keeps appearing to O'Brien is trying to persuade him to let go of his guilt, seek out professional help, and move on with his life.
- Kangaroo Court: While O'Brien's trial isn't seen on-screen, is a safe bet that it was not in any way remotely fair, seeing how Argrathi is ruled by a clearly authoritarian and paranoid regime. In fact, he was found guilty and had been sentenced before his fellow officers even noticed he had gone missing.
- Karma Houdini: The Argrathi aren't mentioned to have faced any consequences for wrongfully convicting O'Brien, or for the psychological damage they inflicted on him.
- Considering they arrested and sentenced what is essentially a foreign national, subjecting him to a cruel mental sentence which had no chance of being ended early, as it takes place mostly instantly to them, this should have been the cause of a MAJOR diplomatic incident between them and the Federation.
- Mauve Shirt: Muniz appears during Miles' first day back at work.
- Mind Prison: The crux of O'Brien's punishment, being forced to spend years on end in a virtual world that existed only for a few hours.
- My God, What Have I Done?: O'Brien after killing Ee'char, as well as yelling at Molly later on.
- Neck Snap: How O'Brien kills Ee'char.
- Nerves of Steel: Bashir shows his yet again, remaining totally calm and soothing while talking O'Brien down.
- The Old Convict: In the simulation, Ee'char has already been in prison six cycles when O'Brien becomes his cellmate, and his coping mechanisms ease O'Brien's suffering somewhat before everything falls apart.
- Please Wake Up: Invoked by O'Brien when he gets into Ee'Char's stash of food, seeing he'd actually saved it for them both, and is wracked with guilt at killing him thinking he'd been keeping everything for himself.
- Posthumous Character: A bizarre example in that technically, Ee'char never existed at all.
- Prison Changes People: The crux of O'Brien's problems after getting out; the prison time technically didn't happen, but all the survival strategies and accumulated traumas are still weighing down on his life.
- Reality Ensues: Starfleet may be Mildly Military, but O'Brien's refusal to comply with orders to seek counselling get him removed from duty.
- Talking Down the Suicidal: Bashir manages to talk O'Brien out of killing himself by reminding his friend that, no matter what he thinks, O'Brien is a good man, and what the Argrathi did to him can't change that.
- There Are No Therapists: There are, but O'Brien spends most of the episode refusing to see one.
- There's No Kill Like Overkill: When preparing to take his own life, O'Brien sets his phaser to maximum; he didn't just intend to die, he planned to vaporize himself.
- [Verb] This!: At his wits end in frustration over being unfairly imprisoned, O'Brien starts pounding on the door of his cell. The PA system chimes in to warn that he will be disciplined if he doesn't stop doing that. O'Brien is having none of it:O'Brien: DISCIPLINE THIS! (kicks the door)
- What Are You in For?: Ee'char asks."Let me guess. Sedition?"
- What Beautiful Eyes!: Ee'char notes that O'Brien is calmer when describing Keiko's eyes.
- Whole Plot Reference: O'Brien's wrongful imprisonment is quite similar to that of Edmond Dantes in The Count of Monte Cristo, with Ee'Char as his Abbe Faria.
- Year Inside, Hour Outside: O'Brien is put through 20 years of imprisonment in just a few hours.
- You Are Better Than You Think You Are: O'Brien admits to Bashir that he thinks killing Ee'char proves he's just become a monster, but Bashir consoles him by affirming that a true monster wouldn't feel the guilt he's feeling now.