DS9 Season 2 Episode 14 Whispers

Plot

Miles O'Brien pilots a runabout through the wormhole en route to the Parada system. He records a personal log of recent events:
Two days ago, O'Brien returned from a meeting with the Paradas to discuss security measures for upcoming peace talks. The next morning, he awoke to find his wife Keiko and daughter Molly dressed and eating breakfast at 5:30 am; both seemed awkward and suspicious around him.
Upon reporting for duty, O'Brien found an officer had begun working on the security arrangements without him, apparently under orders from Commander Sisko. Shortly afterward, he saw Sisko and Keiko having a private discussion on the Promenade. When asked about it, Sisko claimed he was concerned about his son Jake's grades in Keiko's class, but Jake later told O'Brien his grades were fine.
At O'Brien's annual physical examination, Dr. Bashir gave O'Brien a clean bill of health only after an overly long and invasive examination. Additionally, problems O'Brien had been assigned to fix seemed to have been intentionally designed to make him spend additional time repairing them. Reviewing the other officers' logs, O'Brien discovered that Sisko and the others were observing his movements.
O'Brien persuaded Odo to investigate the others' suspicious behavior. But soon, at a meeting in Odo's office, Odo appeared to have joined the conspiracy as well; Sisko, Bashir, and Major Kira arrived to arrest and sedate O'Brien. He overpowered the others and fled the Promenade.
Through maintenance conduits, O'Brien made his way to the runabout Rio Grande and escaped. He contacted Admiral Rollman to warn her that the command crew of Deep Space Nine was under some hostile influence, but she ordered him to return to the station.
Now en route to the Parada system in the Gamma Quadrant, O'Brien is being pursued by the runabout Mekong. He eludes his pursuers and hides behind a moon, and then follows the Mekong to Parada II. There he finds Sisko and Kira with a pair of Paradan rebels, who promise that the explanation to the mystery of the past few days is behind a door. One of the Paradans shoots him, and when the door opens, Bashir is behind it—along with another O'Brien. It is revealed that the Paradan government abducted O'Brien and created a clone who believed he was the real O'Brien, but would assassinate the rebels at the peace talks.
As the clone dies, he asks the real O'Brien to tell Keiko he loves her.