The Federation Alliance operation to retake Deep Space Nine.
After the Dominion captured Deep Space Nine in 2374, the Federation's allies saw the station as a vital target. It controlled access to the Bajoran wormhole, and the Dominion's reinforcements poured through it. If Starfleet could not retake the station, it would struggle to win the war.
Operation Return was the plan to do just that. Captain Sisko led a fleet of Federation and Klingon ships to the station, supported by a daring gambit to prevent the Dominion's reinforcement fleet from emerging from the wormhole. The battle was fierce, with Jem'Hadar and Cardassian forces fighting to defend the station while Starfleet fought its way through.
Sisko's efforts and the intervention of the Prophets, who sealed the wormhole against the Dominion fleet, tipped the balance. The Dominion forces were defeated, and the station was returned to Federation hands. The victory was a major morale boost for the allies and gave them a base for the remainder of the war. Sisko, Worf, Dax, Kira, Odo and Weyoun were among those at the center of the action.