“Return to Grace” is episode fourteen of season four of Star Trek: Deep Space Nine.
Major Kira is heading for a conference at a Cardassian colony to discuss the current problems with the Klingons. Her escort is Gul Dukat, who is now commanding a freighter. Since he didn’t kill his half-Bajoran daughter in “Indiscretion”, but instead took her home to Cardassia, he has suffered a loss of prestige. He is no longer an advisor to the civilian government, his mother has disowned him and his wife, and their children, have left.
On the way to the colony they encounter a Klingon Bird of Prey. Dukat attempts to attack it, but fails, and the Klingons don’t even consider him to be worth destroying. When the freighter arrives at the conference, the colony has been destroyed and all the delegates, Cardassian and Bajoran, are dead.
Dukat wants to do something about this, and Major Kira agrees to help. She may not particularly like Dukat – although he does seem to admire her – but she, too, wants the Klingons to pay for what they did. And Kira has more experience with fighting back against a superior foe than Dukat does – it was Dukat himself and the Cardassians that she was fighting.