DS9 Season 5 Episode 26 Call to Arms

Plot

Upon learning that the Romulans and other major powers have signed non-aggression pacts with the Dominion, Starfleet Command orders Captain Benjamin Sisko to prevent further Dominion reinforcements from reaching Cardassia from their home territory in the Gamma Quadrant. DS9 crew members Jadzia Dax, Miles O'Brien, and Rom devise a plan to block the wormhole with a field of self-replicating, cloaked mines. The mines cannot be activated until they are entirely deployed, which will take some time to complete. Shortly after deployment begins, Dominion representative Weyoun declares that Deep Space Nine will be attacked unless the mines are removed.
Since Starfleet reinforcements are unavailable, Sisko asks the Klingon General Martok to patrol the border while the Defiant continues deployment. Sisko endorses the non-aggression pact offered to Bajor by the Dominion, in the hope that it will keep Bajor out of the coming war. Sisko officiates Rom's marriage to his fiancée Leeta before she and other Bajorans evacuate the station as a result of the non-aggression agreement.
Starfleet personnel remain to defend the station until the mines are completely deployed. Dominion forces attack and are met by DS9's armaments and Martok's vessel, the Rotarran. After the minefield is activated, Sisko orders the Starfleet personnel to evacuate as well, surrendering DS9 to the Dominion. He announces that while the Dominion was occupied with DS9, a combined Starfleet/Klingon task force wiped out an important Dominion shipyard. During the evacuation, Dax and her lover Worf are assigned to separate ships, and agree to marry if they survive the war.
Captain Sisko's son Jake remains on DS9 to serve as a reporter for the Federation News Service while the station is occupied by the Dominion. Rom remains as well, acting as a spy for Starfleet while working at his brother Quark's bar. Bajoran liaison officer Kira disables the station's systems by activating a pre-set computer program; and then she, Quark, and security chief Odo welcome the Dominion occupiers, led by Weyoun and the Cardassian Gul Dukat, to the station. Dukat reclaims the station commander's office, where he finds the baseball Sisko left behind – a message to him that Sisko will return.
Sisko is upset to learn that Jake has remained behind, but cannot return to DS9 and jeopardize his crew for the sake of one man, even his own son. Soon, the Defiant and Rotarran join a massive armada of Starfleet and Klingon vessels.