The One where Klingons and humans are tricked into fighting.
Yet another strange swirly alien makes an appearance as it fees of negative emotion and has the crew and Klingons fight one another.
The Klingons are good, giving a new dimension to their previous appearances and Chekov has some good scenes with his anger. It just feels a bit samey and familiar, plus the ending of them all laughing at the creature comes across as silly.
Still, I've seen worse this Season.
Overall Star Trek Franchise Rating so far: 188/325