Tear Jerker / Uhura's Song

• The deteriorating morale of everyone on the Enterprise as they're forced to watch the plague ravage Eeiauo from the safety of orbit, unable to go down and help. It gets so bad that some crewman who have been isolated for potential exposure to ADF beg to be permitted to beam down to assist the Eeiaouians, even knowing that they'd inevitably catch the disease for sure, just so that they could do something.
• Uhura getting the news that her friend Sunfall has ADF. She nearly breaks down on the bridge, but is thankfully pulled off duty by Kirk so she can talk about her distress.
• Uhura's realization that Sivoan children "earn" their names by incidents in their life, and that Jinx is called that because of failing her Rite of Passage after all of her other teammates died.

  Uhura: "I can't call you Jinx! That's cruel!"

  Jinx: "It's my name, until I can earn another."