On Deep Space Nine, Security Chief Odo is having a "Klingon afternoon." First, Quark complains about an elderly drunken Klingon monopolizing a holosuite. Odo removes the man, Kor, and takes him to a holding cell. A short time later, his friend Koloth comes to release him, but changes his mind when he sees Kor is still quite drunk.
Hearing the names Kor and Koloth, Jadzia Dax realizes why they have come, which is confirmed when they are joined by a third venerable Klingon, Kang. Eighty-one years ago (when Jadzia was still Curzon Dax), the three Klingons led a military operation to destroy the power base of a pirate leader known as "The Albino." The mission succeeded, but the Albino retaliated by infecting each of their firstborn sons with a deadly virus. Curzon, a close friend of the three Klingons, was godfather to Kang's murdered son, and the four of them swore a Klingon "blood oath" to find and kill the Albino. Now, eighty-one years later, Kang says he has finally found him.
Jadzia confides in Kira that she feels obligated to pursue Curzon's oath, but Kira warns her about what killing someone will do to her.
Kang, likewise, tells Jadzia that she is not bound by Curzon's oath, but she insists on joining their quest. Kor, as buoyant as ever, is delighted to have her along. Koloth is dismissive, until she shows him her skills with a Klingon bat'leth. Kang refuses to accept her, until she shames him with his own devotion to Klingon honor, and insists that she have the chance to avenge her godson.
Before Jadzia can request a leave of absence, Sisko beats her to the punch and confronts her in her quarters, refusing her request before she has made it. He cannot condone her taking part in a revenge murder. But Jadzia tells him that she is going, one way or the other, and begs him not to make her disobey a direct order. He does not give her permission to go but does not stop her either, warning her that she might not have a place waiting for her if she comes back.
On the way to the Albino's hideout, the Klingons and Jadzia plan their attack. Kang insists on making a frontal assault on the main gate, promising that the element of surprise and their own prowess as warriors will give them victory. Koloth and Kor march out of the room triumphantly, but Dax stays to confront Kang.
Dax can see that their plan is doomed and demands to know why Kang wants to commit suicide. Kang admits that, when he first learned the Albino's location, he visited the system to see if it was true and was contacted by the Albino. The Albino offered Kang a "glorious" battle against forty of his best men, and Kang accepted. He felt that if they could not kill the Albino, they would die honorably, trying to reach him.
Dax protests, and Kang says that it is their only choice, as the Albino's defenses cannot be defeated. But Dax comes up with an alternative strategy: she can alter their ship's weapons to create a dampening field that will disable all the guards' phasers. If the guards are reduced to fighting hand-to-hand, the Klingons will have a definite edge. Seeing a chance for victory after all, Kang agrees.
When they beam down to the planet, the wisdom of Dax's approach is borne out when scanners reveal that the Albino has booby-trapped the main gate, obviously never intending to keep his bargain with Kang. But by using stealth, and their hand weapons, the Klingons and Dax storm the compound and confront the Albino in his own chamber. In battle with the Albino and his guards, Koloth is killed, and Kang is mortally wounded by the Albino himself. Dax pins the Albino, who taunts her, believing she is not ready to commit cold-blooded murder. She does not, instead allowing Kang the honor, slipping his knife into the Albino's back. "It is a good day to die," Kang utters before dying. Kor and Dax limp out of the compound, Kor singing a melancholy battle song in honor of his fallen comrades.
Dax returns to the station and resumes her post, while casting a nervous glance at both Kira and Sisko, who return it pensively.