Kor is getting old and there is no place in the Empire where his services are needed anymore. He comes to Worf, begging him for an assignment in the fleet, to be able to end his life as he lived it. General Martok, however, has a strong ressentment against the Dahar Master. When Martok was still young, his officer candidature was refused by Kor, preventing him to serve even as a soldier in the Klingon fleet, until the humble origined Klingon gained a battlefield commission. With the memories of the humiliation still vivid, Martok has difficulties accepting a member of his own house helping his old enemy. He finally let Worf do as he pleases, but makes it clear that he would take no responsibilities in the matter.
Worf then offers Kor to serve as third officer on the lead ship in a raid on Trelka V. This has the side effect of greatly irritating Martok while everyone of his officers are thrilled to have the living legend on board. Only to make things worse, Martok's attack plan bears many similarities to the one used at Caleb IV, a famous raid executed by Kor and Kang against the Federation. When the raid effectively takes place, Martok and Worf get wounded and the command falls to Kor. In the following moments, the old Klingon confuses the reality with his memories and almost gets everyone killed before Worf is able to knock him out.
When the battle is over, Martok comes to the mess hall, where Kor already is, to gloat about the recent events. The general doesn't take all the satisfaction he though he would, as the Dahar Master looks much more like a glimpse into what awaits every long-living Klingon than like a threat anymore.
Soon after, ten Jem'Hadar ships show on sensors, tracking the Martok's squadron even if they are now cloaked. As they are slowly gaining on them, a plan is devised to makes the whole squadron drop out of warp for a short amount of time to let the remaining Birds-of-Prey make it to the rendez-vous with the USS Defiant. Worf volunteers for the mission but Kor takes his place, stunning him with a hypospray, at the last minute. The Dahar Master is finally able to engage the whole Jem'Hadar squadron (with a minimal crew of six), effectively saving the remaining Klingon ships and ending his days (it seems, as the sensor contact is lost before the battle is over) as a true warrior.
A subplot of the episode happens at Deep Space 9. From an incomplete conversation he eavesdropped, Quark understands that Ezri Dax wants to engage in another relationship with Worf and he decides, with the not-so-wise advice of apprentice-barman Jake, to declare himself. In the following conversation with Ezri, she rectifies the truth, but she is still charmed by the kind, dear and embarrasing declaration the Ferengi just made to her.