Kai Opaka, the spiritual leader of the Bajorans, comes aboard the station and requests a tour from Sisko, but during the tour she subtly asks him to take her through the Wormhole. Against his better judgement he complies, and he, Bashir, 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.
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, regenerated by some form of extraterrestrial nanotechnology. 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 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, Kira must face her personal demons: 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 keeps 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 here now, but reassures him that their Paths will cross again.