S1E4 · Code of Honor

The Enterprise arrives at the planet Ligon II to acquire a vaccine needed to combat an outbreak of Anchilles fever on Styris IV. The crew, possessing little information on the Ligonian culture, finds that it follows strict customs of status similar to ancient China. Specifically, while the men in their culture rule society, the land itself is controlled by the women. Lutan (Jessie Lawrence Ferguson), the Ligonian leader, transports up to the Enterprise to provide a sample of the vaccine, and is impressed by Lt. Tasha Yar 's status as head of security.

Yar further demonstrates her aikido skills against a holographic opponent for Lutan on the holodeck. After a tour of the ship, Lutan and the Ligonians abduct Yar as they transport back to the surface. Captain Jean-Luc Picard (Patrick Stewart) demands that Lutan return Yar, considering the kidnapping an act of war, but receives no response from the planet. After consultation with his officers, Picard determines that Lutan took Yar in a " counting coup " as a show of heroism. Picard contacts Lutan in a more peaceful manner, who grants permission for the Enterprise crew to beam down to the planet and promises to return Yar after a banquet in his honor.

Lutan announces at the banquet that he wishes to make Yar his "first one", surprising not only the Enterprise crew but also Yareena (Karole Selmon), who was already Lutan's "first one." Yareena challenges Yar to a fight to the death to claim back the position. When Picard objects to the fight, Lutan refuses to give the Enterprise the rest of the vaccine unless Yar participates. The crewmembers investigate the combat ritual and find that the weapons used are coated with a lethal poison and that it is Yareena's wealth to which Lutan owes his position.

Picard prepares to have Yar beamed to the Enterprise should she be harmed in the battle. As the match progresses, both Yareena and Yar are equally skilled, but Yar eventually lands a strike on Yareena. Yar quickly covers Yareena and orders the transport of both of them to the Enterprise against the demands of Lutan. Aboard the ship, Dr. Beverly Crusher (Gates McFadden) reaches Yareena moments after death, but is able to counteract the poison and revive the woman's body. When Lutan demands to know the fate of Yareena, Crusher reveals that Yareena died, thus ceding the match to Yar and breaking the "first one" bond.

Yareena is now free to select a new mate; she chooses Hagon (James Louis Watkins), one of Lutan's bodyguards, effectively stripping Lutan of his position of power and making him her "second one". Hagon lets Yar go and gives the Enterprise their full supply of vaccine.