Worf and Dax have a fight to decide which Klingon weapon is better. Worf accuses her of wearing a low-cut top to distract him. They're interrupted by Odo, who calls Worf to an airlock to talk to a drunk Klingon. It turns out to be Kurn, Worf's brother, who's asking Worf to kill him. Right. Kurn wakes up in Worf's quarters and begins bitching about how cushy Worf has it and how the House of Mogh has been stripped of its land and ships.
Meanwhile, O'Brien and Kira are on their way back to DS9 when there's a flash of energy nearby. They move in to investigate, and a Klingon Bird of Prey decloaks and tells them to get lost. They set course back to the station, but monitor the area of the explosion.
Dax talks to Quark and finds Worf's been ordering Klingon incense. Wonder what that smells like. Wet targ, probably. She talks to Odo, finds out Worf met his brother, and the pair hurry to Worf's quarters where he's just stabbed his brother in the chest. Odo informs him that if Kurn doesn't survive, there's a murder charge. Sisko is very annoyed. Dax reports that Kurn's going to survive and tries to explain about Klingon rituals, but Sisko explodes.
Sisko also tells Kira to take the Defiant to check out what the Klingons are up to, just in case you were wondering about the B plot.
Kurn is very annoyed to find he's still alive. That's a nice shot of Worf looking down at his brother. BTW, if Kurn sounds familiar, that's because Tony Todd also played the elderly version of Jake in "The Visitor". Dax apologises to Worf for interfering in the ritual, and suggests Kurn ought to stay on the station, and possibly join Odo's security force as a job. Odo grudgingly accepts and says Worf's in his debt. Kurn turns out to be quite an impressive security officer. Odo is pleased. Kurn finds the uniform uncomfortable. Not enough leather, I guess.
The Defiant detects more cloaked ships, and suddenly a damaged Klingon battle cruiser appears, refuses help, then changes their mind and accepts the offer of a tow to DS9.
Worf's called to the infirmary - Kurn's been shot with a disrupter over some contraband. Odo says he's fired.
Bashir says there's nothing odd about the injured from the Klingon ship. And they conclude that the ship struck a cloaked mine. The only way to find any other mines out there, would be to get the co-ordinates from the Klingon ship. Worf thinks they can use Kurn to get the information, but Kurn's not keen. Worf talks him into it, and the two Klingons are made up to look like they came from the ship. They board the ship and try to access the database, but are soon caught and bluff their way until Kurn shoots the other Klingon and starts whining about honour.
They get off the ship with the information and take it back to Sisko, who's very pleased. Worf is troubled by the fact that he didn't notice the Klingon officer was going to kill him, but Kurn did.
Kira and O'Brien take the Defiant to the minefield, and warn the Klingons they're about to start blowing up the mines. With no response, they detonate the first mine. With still no response, they blow up a bunch more mines, and a bunch of Klingon ships decloak and turn tail.
Worf finds Kurn complaining about how suicide is dishonorable and how he's a burden to Worf.
You know, if you make a drinking game and take a swig every time someone says the word "honour", you too can get as drunk as Kurn.
Worf asks Bashir to memory-wipe Kurn, and Kurn wakes up thinking he's a Klingon from another house. When he asks Worf if he's part of the same house, Worf simply says he has no family. Awwwwww.