The Klingons intercept a message from the remnants of the Maquis--apparently, a bunch of missiles are on their way to Cardassia, cloaked, and unstoppable. The Maquis have been totally wiped out by the Dominion, and this last gasp appears to be a vindictive push into war. Sisko has to stop them, but he is going to need the help of one person: Michael Eddington, the former Starfleet officer he helped put away by zapping Maquis planets with deadly toxins. There is no love lost between the men, but Eddington eventually comes around to help. When the two finally reach the launch site from where the missiles can be deactivated, it is crawling with Jem'Hadar, and we are introduced to a few last Maquis, including a woman who just so happens to be Eddington's wife.
This episode more or less fills in Eddington's motivation for the Maquis, and fleshes out his character a great deal. However, it is also the final goodbye to Eddington, whose death is fitting. It's a pretty good episode, with some touches of mordant humor ("It could be me holding the pipe") that fit in quite well. One of the better efforts in a pretty good season.