One of the Teenax who attacks Kirk becomes ill after the attack, because human blood is toxic to Teenax. McCoy places Teenax (all the Teenax are called Teenax; they insist that as they speak it, each name is distinct) in stasis but cannot cure it. However, the Fabona (who look like 9' tall sunflower plants) offer a second artifact with healing powers. This time, the Teenax choose to overlook the fact that the artifact may be "stolen" in order to save the life of their countryman.
B plot: Scotty plays a practical joke on Keenser, but its race is unfamiliar with the concept. Keenser takes it in stride, but an attempt to reciprocate the practical joke goes awry.
B2 plot: Kirk's upcoming birthday; subspace communication with Commodore Paris about promotion to a desk job.
B plot: Billed as the Federation's largest engineering effort to date, Yorktown Station is not all it is hyped to be. Problems range from wonky comms to broken replicators. "At least the gravity stayed on this time!" quips Sulu's partner (whose name we actually learn) when the lights fail during a romantic dinner.
As we watch the time-lapse construction of NCC-1701-1, voice overs:
Kirk: That ship is beautiful. Too bad I'll never fly her.
Paris: She's is yours if you want her. Perhaps your promotion was just a glitch in the Yorktown's computers
Spock: [stilted language that he was "illogical" to dump Nyota]
Nyota: If that's an apology, I accept.
(My friend Michael wants me to add: and then they find out the new Enterprise is too big to fit in the passage from the construction dock to space)