1/2
One of the more action-adventure episodes in all of Original Trek. Kirk and an evil Romulan engage in a cat & mouse battle on the edge of the Neutral Zone. When it is discovered that the Romulans racially resemble Vulcans some bigotry comes out of the mouth of Redshirt (kinda) Lt. Stiles. In the upper part of the frame sits Lt. Sulu as Kirk argues about the dangers of prejudice. Figuring this is about 20 years after WWII (and at the head of Vietnam), it may not have been such a subtle moment as it seems today. Anyhow, on watching this episode again, it strikes me that maybe the Romulan was on a Death Wish trip – he’d love to avoid another war, and letting Kirk blow him out of the water may be the only way to achieve this. The repeated special effects shot of phaser blasts around the Romulan ship (with outta control brass horns and swirling strings on the soundtrack) is one of the great over-the-top audio/visual moments in all of Trek.
It might interest you to know that Roddenberry got the idea for this episode from the movie “The Enemy Below” staring Robert Mitchum. Very similar plots but very well reworked for Star Trek.
It turns out Roddenberry was a fan of the movie.