Sisko discovers a stable wormhole and must explain linear existence to the aliens within it, while Kira bluffs a Cardassian fleet that threatens the station.
Sisko and Dax find a stable wormhole to the Gamma Quadrant in the Denorios Belt. Dax is sent back to the station, but Sisko is held inside by beings with no concept of linear time or physical existence. Kira has the station moved to the mouth of the wormhole, and when Dukat follows Sisko in and vanishes, Cardassian warships blame the Bajorans and demand the station's surrender, which Kira stalls with a bluff.
Trying to explain linear life, Sisko is made to see that he keeps returning to the moment of Jennifer's death and has not let go of his grief. He persuades the beings to let ships pass and emerges towing Dukat's damaged ship, ending the Cardassian attack. Sisko then tells Picard he will stay in Starfleet, and the two part on better terms.