As part of an exchange program, the Enterprise plays host to Klingon officer Kurn. Kurn hands Worf the surprise of his life when he informs the lieutenant that they are brothers, separated after their parents were killed in the Romulan assault on the Khitomer Outpost. Evidence has surfaced that indicates their late father Mogh may have aided the Romulans, and now Worf, the eldest son, must go before the Klingon High Council to defend his family's honor. After the trial begins, Kurn, who is serving as his brother's cha'Dich, is attacked and severely injured by Klingon assassins. Worf shocks the council when he appears with his new cha'Dich: Captain Jean-Luc Picard. Picard must prove that Mogh was innocent, or surrender Worf to meet the punishment for his father's treason: death by execution.

Charles Cooper (Chancellor K'mpec)
Tony Todd (Commander Kurn)
Patrick Massett (Duras)
Thelma Lee (Kahlest)

• When Kurn is injured, Picard becomes Worf's cha'Dich ("second").
  
• Duras' father Ja'rad was actually the traitor at Khitomer. To protect the honor of the Empire and to prevent cival war, Worf accepts discommendation.
  
• The U.S.S. Intrepid NCC-38907 was the first Federation starship to respond to the Romulan attack on Khitomer on Stardate 23859.7. Captain Drew Deighan was the commanding officer (and was named for the episode's story writer).
  
• This is the first time we see the Klingon Homeworld, Kronos (transliterated as Qo'noS from the Klingon script).
  
• The Klingon language was developed by linguist Marc Okrand and was used first in this episode. The language is featured in all future episodes and movies.