DS9 Season 1 Episode 13 Battle Lines

Plot

Kai Opaka, the spiritual leader of the Bajorans, requests a tour of Deep Space Nine from Commander Sisko. During the tour, she subtly asks him to take her through the wormhole. Against his better judgment he complies, and he, Dr. Bashir, Bajoran liaison officer Kira, and Opaka travel to the Gamma Quadrant. There they receive a distress signal from an unknown source. Opaka tells Sisko not to hold back on her account, so the group goes to investigate.
They find a planet with a network of satellites, one of which is malfunctioning. The runabout approaches the planet and one of the satellites attacks it, forcing them to crash-land. Opaka dies in the landing, which devastates Kira; however, her mourning is interrupted by a group of people called the Ennis, led by Golin Shel-la (Jonathan Banks).
The Ennis explain that they are at war with a group called the Nol-Ennis, who could attack at any minute. They take Sisko, Bashir, and Kira to a cavelike dwelling, and as predicted the Nol-Ennis attack within minutes. Many of the Ennis are killed fending off the attack, but after the battle Kai Opaka enters the cave, resuscitated by some form of nanotechnology that pervades the planet. The same technology revives the Ennis and Nol-Ennis, but rather than a blessing it is a curse; both groups were sent to the planet as punishment for centuries of conflict, doomed to die over and over.
As Deep Space Nine officers Dax and O'Brien search for the group, Sisko gets the Ennis and Nol-Ennis to agree to meet in an effort to negotiate peace. Meanwhile, the conflict between the groups reminds Kira of her own trauma, which she discusses with Opaka: years of fighting the Cardassians on Bajor have taken their toll on her and she has known nothing but violence since she was a child. However, while Kira is reconciling her problems, the Ennis and Nol-Ennis refuse to fix theirs and resume fighting.
The groups are revived once more and return to their respective camps, but by this time Bashir has discovered that the technology prevents those it revives (including Opaka) from leaving the planet. O'Brien and Dax find Sisko, and Opaka informs him that she will stay with the Ennis and Nol-Ennis. She says it is time for them to begin their healing process just as Kira has begun hers. Meanwhile, the Ennis and Nol-Ennis resume fighting. Before O'Brien transports Sisko, Bashir, and Kira to the runabout, Opaka tells Sisko that her work is there now, but reassures him that their paths will cross again.