Star Trek: Deep Space Nine: Season 2, Episode 19 - ProjectFreeTV

2 - 19: Blood Oath

Three legendary Klingon warriors reunite on DS9 seeking Curzon Dax, with whom they entered into a blood oath to one day exact revenge on their sworn enemy. Finding Jadzia to be as worthy a warrior as they felt Curzon to be, they invite her to join them on their crusade.