"Wrongs Darker than Death or Night" (season six, episode seventeen; 30 March 1998): Wikipedia-link.
Commentary: "Wrongs Darker than Death or Night" is Star Trek at its best, showing the moral & emotional complexities of life, memory, & the past. By this point in the show, after "Waltz," Gul Dukat is in full psycho villain mode, living only to destroy Bajor & its Prophets, & he confronts Major Kira Nerys with the knowledge he & her late mother, Kira Meru, were lovers. Kira convinces Captain Sisko to allow her to investigate these claims using the Orb of Time (which also facilitated the time travel in "Trials and Tribble-ations" [season five, episode six]). She argues that if the Prophets permit her to travel in time, they will also protect her from damaging the timeline. I like the faith aspect of that argument, that by this point in the show Sisko is comfortable with her appealing to him as the Emissary, not as a Starfleet captain, but it doesn't square with the Orb of Time's first appearance in "Trials and Tribble-ations," when the crew had to take active measures to prevent a Klingon agent from altering the timeline by murder Captain James T. Kirk.
In any event, Kira discovers that Dukat had indeed told her the truth, that her mother had not died in a refugee camp as she'd always been told, but that her mother had been taken as a "comfort woman" to Terok Nor, the original Cardassian name for Starbase Deep Space 9, & had spent seven years as the mistress of Gul Dukat. Not only that, but Dukat had kept his promise to Meru to take care of her family, providing them with extra food & allowing them tore turn home from the refugee camp. Kira Nerys benefitted directly, though unknowlingly, from the collaboration of her mother, Kira Meru.
