Walter Koenig wrote the episode, "The Infinite Vulcan". Hope there's no nuclear wessels involved.
Kirk and Co. beam down to a planet. Sulu is poisoned by a weird plant. More plants--this time humanoid--appear and save Sulu. It turns out most of their people died from a previous human expedition--they couldn't handle human germs. Weird bats with tentacles (a common theme on this show) fly in and grab Spock. A huge guy in a skirt appears, and tells them to leave. More bats force them to transport out.
Kirk has Scotty making new weapons to fight the plants. Uhura finds out the huge skirt guy was involved in the Eugenics Wars--he's the fifth clone of the original. They go back down to the planet with the new weapons. The plants are getting a fleet of ships ready. Kirk grabs one of the plants and convinces him to take them to Spock. They go underground, but get attacked. They find Spock and Spock II (a huge clone of Spock). They fire their new weapons--basically weed killers--to take out the bats. Spock's mind is drained, but they try to escape with him--the Spock clone blocks the way.
Scotty and Uhura try a desperate move to communicate with the landing party. Spock II answers the call--Uhura sends a message about the huge skirt guy wanting to create a master race to enforce peace. Kirk explains that the galaxy is peaceful now. Spock II mind melds with Spock, and saves the latter. They agree to leave the huge skirt guy and Spock II on the planet to do more peaceful work.
Some things to look for:
- Although he can't figure out what the poison is, McCoy knows that Sulu will be "dead in a minute" if something isn't done
- The bats make the generic "screech" sound heard on Hanna-Barbera adventure cartoons
- At one point, Spock is seen on the bridge--although he's already been captured on the planet
- Spock II has a copy of Spock's uniform, which makes it easier to animate but makes no sense. Of course, neither does the huge skirt guy.
- Spock II also has a bit of a gut
- Since they leave Spock II there, they could have retrieved him after the original died in Wrath of Khan--if this was actually in continuity
- Sulu does the cartoon wink to close out the episode
Remember, you can play along by watching the show on Netflix!