Plot

A Klingon commander comes aboard the Enterprise in an officer exchange program initiated by Starfleet, much to the chagrin of the crew.

Commander William T. Riker is charged with hosting Klingon commander Kurn, who takes his place as first officer as part of an exchange program. As expected, his ruthlessly authoritative command style gets on everyone's nerve, but the worst is yet to come: Kurn reveals himself as Lieutenant Worf's younger brother, and demands he joins him in dealing with a blood feud, as their late father's honor is challenged by accusations of treason to the Empire in league with the Romulans during a bloody attack. The Enterprise sets course to the Klingon first city, while Picard fears legal and diplomatic repercussions. Data finds indications the Klingon records were doctored, possibly at Klingon High Council level, so the Enterprise crew sets out to find out the truth...—KGF Vissers

As part of an ongoing exchange program with the Klingon Empire, Commander Kurn comes aboard to serve as the Enterprise's executive officer. Kurn is well versed in Federation protocols and is qualified for the position in all respects except perhaps one: the way in which he treats subordinates. He demands complete and unquestioning loyalty from everyone around him. Kurn had specifically requested assignment to the Enterprise and with good reason: he is actually Worf's younger brother who, unknown to Worf himself, survived the attack that killed their parents. He's come to Worf with news that their father has been declared a traitor and that as the older brother, he wants Worf to lead the challenge. They return to the Klingon homeworld accompanied by Captain Jean-Luc Picard intent on clearing the family name.—garykmcd

Commander William T. Riker is charged with hosting Klingon commander Kurn (Tony Todd), who takes his place as first officer as part of an exchange program. As expected, his ruthlessly authoritative command style gets on everyone's nerve, but the worst is yet to come. Kurn makes everyone work double shifts and is specifically tough on Wesley & Worf. Riker asks Kurn to let up a little, but Kurn is very adamant about running things his own way.

Worf confronts Kurn and says that Kurn has dishonored him at every opportunity. Kurn reveals himself as Lieutenant Worf's younger brother. He was left behind with his uncle while Worf and his parents went to the outpost at Khitomer. When Worf's parents died, Klingon high command simply assumed that Kurn had died with the family. Kurn demands that Worf joins him in dealing with a blood feud, as their late father's honor is challenged by accusations of treason to the Empire, by being in league with the Romulans during a bloody attack on the Khitomer outpost. Charges are made by Duras (Patrick Massett), son of Worf's father's greatest rival. In Klingon tradition, the family is responsible for a person's actions. So, if Worf fails in his challenge (as the elder son, the challenge is his to make), he will be executed.

Picard decides to be at Worf's side when he makes the challenge. The Enterprise sets course to the Klingon first city, while Picard fears legal and diplomatic repercussions. At the Klingon high council hall, Duras accuses that Mogh, Worf's father, sent Khitomer access codes to the Romulans, which allowed them to bypass the security matrix placed around the outpost. K'Mpec (Charles Cooper) the High council chairman calls a recess and advises Worf to drop the challenge and retreat. The ruling has no implication on Worf's career at Starfleet. He says that Worf should leave the past and protect the present. The challenge will be forgotten if he goes. Duras finds out that Kurn is Mogh's another son and has him attacked and badly injured.

Data finds indications the Klingon records were doctored. Klingon's had captured a Romulan ship whose logs provided more info on their attack at Khitomer, and Intrepid was the closest Starfleet vessel who was monitoring the situation at Khitomer.. The Logs from the Romulan ship and Intrepid match, but they go out of sync at the precise moment when Mogh was supposed to have transmitted the codes to Romulans. This looks like a fabricated entry in the Romulan logs. Data speculates that the fabrication took place possibly at Klingon High Council level, so the Enterprise crew sets out to find out the truth.

Beverly finds that a Klingon woman Kahlest (Thelma Lee) also survived at Khitomer and was treated at Starbase 24. She is on the Klingon home planet. Picard seeks her out. Kahlest agrees to cooperate and brought to the High Council, but K'Mpec relieves her without hearing her testimony. K'Mpec reveals that he knew it was Duras' father Ja'rod who had colluded with the Klingons, but Duras's family is powerful, and someone had to be blamed.

Picard refuses to sacrifice Worf and Kurn, even though the Klingon high council knows the truth. But K'Mpec cannot allow civil war for the honor of a single family. But Worf is willing to die for the unity of the Empire but wants his brother Kurn to be spared. This is not acceptable to Duras. As the only solution, Worf accepts exile from the Klingon society to allow Kurn to live with his honor intact. Picard takes Worf away.