Worf gets an unexpected visit from his younger brother Kurn. Kurn confronts Worf about the dishonor Worf has brought upon their family, the House of Mogh, by rejecting the Klingon Empire's war with the Cardassian Empire. As a result of Worf's choices, his family has been stripped of its wealth, honor, and political power. Kurn has lost everything, and wants Worf to give him back his honor the only way he can, by having Worf ritually kill him. Worf begins the ceremony, but Worf's crewmate Jadzia Dax figures out what he is planning. She and security chief Odo rush to interrupt the ceremony but only after Kurn is stabbed. Dr. Bashir manages to save him. Captain Sisko is furious and forbids Worf from completing the ceremony.

Kurn, without an honorable life or death, places himself in Worf's hands. At Dax's suggestion, Worf asks Odo for a favor and gets Kurn a position with Odo's security force. However Kurn soon loses his job when he allows himself to be shot without any attempt to defend himself.

Meanwhile, mysterious explosions and cloaked Klingon vessels have been observed near Bajoran space. Eventually it is discovered that the Klingons are secretly mining the space around Deep Space Nine in preparation for a future war. Worf and Kurn are sent on an undercover mission to discover the mines' locations and activation codes. They are able to access the data, though Kurn is forced to shoot a Klingon officer in order to defend Worf. Using this intelligence, Major Kira is able to detonate the mines and flush out the cloaked Klingon vessels.

Having killed a man who was acting in defense of the Klingon Empire deepens Kurn's depression. Worf is distressed that he did not realize the Klingon officer intended to kill him—feeling that a real Klingon would have. He comes to the conclusion that he is not of the Klingon or human world, but he has his Starfleet rank, and Kurn has nothing at all. To allow Kurn to live an honorable life as a Klingon, Worf has Dr. Bashir erase Kurn's memory so he can be given a new identity. Kurn—now "Rodek"—is then entrusted to a family friend who agrees to take him in as a son. In the last scene he looks to Worf and asks him, "Are you part of my family?", to which Worf replies: "I have no family."

The producer considered the possibility of bringing back Rodek, son of Noggra, but the follow-up never happened on screen.^[1] Rodek returned in several Star Trek novels including "A Burning House" by Keith R. A. DeCandido set four year later, where his memory begins to return.^[2]

In a 2013 review, Zack Handlen The A.V. Club wrote, the story works "because of the emotion behind it. The details don’t matter; what matters is that Worf is permanently cutting himself apart from the only Klingon relative he has left. To save his brother, he has to lose him, and it's ridiculous and tragic all at once."^[3] Tor.com rated the episode 7 out of 10.^[2]

In 2018, SyFy included this episode on their Jadzia Dax binge-watching guide.^[4]

In 2020, Io9 said this was one of the "must watch" episodes from the series.^[5]

• "Sons of Mogh" at IMDb  
• Sons of Mogh at Memory Alpha
• "Sons of Mogh" at Wayback Machine (archived from the original at StarTrek.com)