16. Journey To Babel
There are a lot of "firsts" on this list, and this episode was the first to introduce Spock's parents, the legendary Ambassador Sarek and his wife, Amanda. Those who are fairly new to the franchise are probably well aware from the reboot, at least, that Spock and Sarek don't necessarily see eye to eye on Spock's life choice to join Starfleet rather than attend the Vulcan Science Academy and in Sarek's debut, the two of them are practically estranged. In this episode, the Enterprise is tasked with transporting Sarek and several other delegates to the neutral planet Babel to negotiate the entrance of the Coridan system into the Federation. After a fight breaks out between Sarek and a Tellarite ambassador, the Tellarite is murdered by way of an ancient Vulcan execution, making Sarek the prime suspect. These allegations cause Sarek's heart to give out and tensions on the ship reach a breaking point, resulting in Thelev, an Andorian ambassador, to critically injure Kirk leaving Spock in command even though Sarek requires a blood transfusion from Spock in order to stay alive. The Andorian is thrown into the brig, and when searched his antennae come right off; he is not even an Andorian, rather a spy implanted to create chaos among the delegation and collapse negotiations. Coincidentally, at the same time an unidentified vessel is giving chase to the Enterprise, presumably the spy's ship, and damages the Enterprise. Kirk shuts down all power, thus playing dead, and then launches a surprise attack, causing the ship to self destruct and the spy to drop dead from suicide by poison.
15. Errand Of Mercy
"For everything... there is a first time," Mr. Spock said in Star Trek II, and why is this episode on the list? No reason other than it introduces arguably the most well known aliens of the entire Trek universe, the warrior like Klingons. Upon the breakdown of negotiations between the Federation and the Klingon Empire, the Enterprise is ordered to the planet Organia along the Klingon border to block any Klingon attempt at annexation of the planet into the Empire. With Kirk and Spock on the planet surface, the Klingons manage to take over the planet without any resistance, with Kor being named the military governor. The Organians, who refuse to resist the Klingons in any way, give Kirk and Spock up to the Klingons where they will be subjected to a "mind scraping" interrogation that would render the both of them into a vegetative state. The Organians then help Kirk and Spock escape and provide them shelter from the Klingons, but as the Klingons discover them, the Organians reveal themselves as advanced god-like beings who immobilize both the Federation and Klingon fleets and force them to resolve their differences.