[TNG] Season 4, Episode 7: Reunion
Rating: 4
This episode establishes a few major elements to the Klingons: The villainy of the house of Duras, members of which pop up throughout The Next Generation; and Gowron, who plays a significant role in TNG and especially in Deep Space Nine. It also introduces Alexander, Worf’s son, who isn’t a problem in this episode but is a pretty consistent bummer in all his subsequent appearances. Aside from the continued intrigue of the Klingon high council and a deftly plotted (though not the most original) mystery, the main reason “Reunion” earns a four is because it contains some of the best Worf scenes in the entire franchise. His connection to K’Ehleyr feels pretty real, and Worf’s reaction to her death make sense but also catches the viewer off guard. It’s uncommon for Trek to resort to this type of violence, but I think it’s pretty effective in this case.
Read more at Memory Alpha
Notes:

The Klingon chancellor has been poisoned. He wants Picard to mediate the selection of the next chancellor while figuring out which of the two candidates murdered him.

Worf is the boy’s father, but Worf can’t claim him because then he would share in Worf’s dishonor. K’Ehleyr doesn’t buy that Worf gave up the fight for his father’s honor.

He fights Duras and straight up MURDERS him! I like how Riker realizes what Worf is going to do and scrambles to stop him, but doesn’t arrive in time.

Worf mercifully (for the sake of the kid, Worf, and the audience) sends the kid to live with his grandparents on Earth.
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