When a Federation freighter goes down over the war-torn colony of Turkana IV, the Enterprise goes in to rescue the survivors. The survivors, however, are now being held hostage by the Alliance, one of the colony's warring factions. The other faction is the Coalition, and is led by Hayne (Don Mirault), who proposes to work with the Enterprise crew in order to rescue the hostages. Turkana, by the way, was the home colony of deceased Enterprise crewmember Tasha Yar.
Story linchpin: Among the Coalition's soldiers is Tasha's younger, hotter sister, Ishara (Beth Toussaint, who looks like the younger, hotter sister of Linda Hamilton). She volunteers to help the Enterprise crew in their rescue attempt. Obvious question of the hour: Can the crew trust her, or does she have her own agenda on behalf of the Coalition? Fortunately for "Legacy," the crew is smart enough to pose this question aloud up front. Picard decides to attempt cooperation with the Coalition in the absence of a better option.
"Legacy" is a competent but unremarkable affair: Nothing hugely wrong with it, but not a whole lot in its favor, either (unless you count Beth Toussaint in a one-piece). It's all but impossible to care about the random, overly simplistic sociopolitical conflict between the Turkanan factions. We've seen the "two warring factions" plot on Trek plenty of times, and "Legacy" gives us precious little political intrigue to make this remotely compelling. The action scenes consist of competent but unremarkable shootouts in underground tunnels.
Faring better, but still plenty shy of great, is the material surrounding whether the crew can trust Ishara. Some scenes depicting the developing friendship between Ishara and Data are palatable, but we spend much of the hour waiting for the other shoe to drop and Ishara's betrayal to be revealed. Ishara is at the mercy of an inevitable plot. And when she's not, her status as "Tasha's sister" is mined too heavy-handedly for my tastes.