Sisko, Odo, O'Brien, and Worf are sent on a mission to expose Chancellor Gowron as a Changeling infiltrator, only to discover that it was Martok who had been replaced. The Changeling impersonating Martok is killed, but Gowron is still not ready to end the war with the Federation. The crew is able to capture a crashed Jem'Hadar ship and return it to Starfleet. Worf helps Quark woo his ex-wife Grilka, while he and Jadzia Dax start a relationship initiated by Dax.