Tribbles eat, reproduce, and cause all kinds of trouble.
Harry Mudd causes more problems for Captain Kirk, this time with a planet full of androids.
Dr. McCoy alters history, and the way to stop it will break Kirk’s heart.
The Enterprise meets another godlike being, and this one likes to play games more than most.
Harry Mudd appears for the first time, and we get more outdated gender politics.
Star Trek started here…sort of. Maybe. Not really.