“Behind the Lines” is episode four of season six of Star Trek: Deep Space Nine.
The Defiant is operating out of Starbase 375 and O’Brien walks into the mess hall carrying up a used up power cell from the phasor array, something they have been holding a ceremony around. Following which Admiral Ross walks in and asks to speak to Sisko. According to the admiral, Starfleet Intelligence has just discovered how the Dominion is constantly keep ahead of the Federation and Klingon Empire – a huge sensor array, capable of even detecting cloaked ships. Admiral Ross wants Sisko to draw up on attack plan to destroy the array. Sisko’s plan is accepted, but before it’s put into place, Admiral Ross promotes Sisko to be his adjutant, as his former one has just been promoted. Dax will captain the Defiant on the mission instead.
On DS9, Major Kira are working together. Rom had got hold of the Cardassian Damar’s pad, in which he suggests poisoning the last supply of ketracel-white, if the Dominion can’t bring down the minefield blocking the wormhole, so that they don’t have out of control Jem’Hadar on their hands. The pad has wound up in the hands of the Jem’Hadar. A fight breaks out in Quark’s between the Cardassians and the Jem’Hadar, with multiple casualties on each side. Gul Dukat is not happy about this, nor is Weyoun. Weyoun suspects something, but wants to make sure the Cardassians and Dominion still appear to be allies. Odo is also not happy about the fight being incited – he had said it was a bad idea. Kira is concerned that Odo has forgotten about the war.
Another Founder, one who Odo has met before, who was trapped in the Alpha Quadrant, has arrived on DS9 to see Odo. The last time Odo saw her was in “Broken Link”, when the other shapeshifters turned Odo into a solid. She says the others have forgiven Odo; Odo says he has not forgiven them. The Founder is not happy that the minefield is still up, and states as much to Weyoun and Dukat. When Odo links with the Changeling, Kira becomes concerned that she is manipulating him. Again. Especially as being linked affects Odo very strongly.