“Visionary” is episode seventeen of season three of Star Trek: Deep Space Nine.
Chief O’Brien gets injured whilst fixing something on the station, and the injury starts having a peculiar side effect. O’Brien starts seeing events happening a few hours in the future; in fact, he is being physically transported into the future. The radiation that the chief was exposed to seems to be interacting with the effects of a quantum singularity near to the station. The events aren’t always good; O’Brien sees himself dead on two occasions and the station destroyed on a third. Somehow, he has to try and learn enough about what happened in the future to stop it.
A delegation of Romulans are also visiting the station, wanting an update on all the information from the Gamma Quadrant, which they are entitled to after loaning a cloaking device to the Defiant. A group of Klingons also arrive, and start causing trouble.