Just watched this episode again for the first time in over 20 years.

I agree with both epaddon's comments and Mike's review. There were too many plot holes and gimmicks which were tough to swallow.

It's too bad, because this was an okay episode which could have been very good, with just some more careful writing.

My biggest problem with the episode was the poor usage of the Trikonis/Harner switch. I was able to get past the super-lookalike Russian double for Harner, even with as far-fetched as it was. However, the second half of the episode went into the weeds with this gimmick, and didn't make much sense. Somehow they were able to brainwash the real Harner into doing their dirty work, after the military dentist became suspicious about fake Harmer's Moscow-like dental work. So presumably they took fake Harner off the job at that point, fearing this would get exposed, and replaced him with brainwashed real Harner. But if such a thing was so easy to do, why not just kidnap the real Harner and brainwash him in the first place? Why all the risky plans for the double to take Harner's place? They also never explained exactly how they brainwashed Harner, which kinda bothered me.

I think it would have been a lot better if they caught fake Harner after he completed his mission, and then he made a deal to give up his comrades in exchange for some kind of lesser sentence. Then he could have told McGarrett where to find them, and agreed to pretend to show up and meet them there, with Five-O ambushing and arresting everyone. Real Harner could have also been there, with the (foiled) plan to kill him right before escaping onto the sub. This modification could have avoided the need to use the brainwashing plot device.

The Maria Robles (Maud Adams) character was one of the more ruthless female villains. While she was very beautiful, unfortunately her character's beauty wasn't really necessary for the Russian plot to succeed, and in fact hindered it, as it made her quite memorable everywhere. (Notice witnesses kept describing the "beautiful woman" they kept seeing in places of interest for Five-O.) Her looks didn't figure into any of the plans, except to seduce the dentist, who presumably could have been killed without having to set up that whole ruse at the bar! Russia would have been better off sending an average looking woman to run the plan, as she would have been less memorable. Of course, then the male audience of 1977 wouldn't have gotten to ogle her in a bikini, which was the main reason Adams was cast.

Adams, by the way, is 75 years old, and still alive.

Commander Chris Nolan (Geoffrey Lewis) spent a lot of time with McGarrett in the episode. Lewis died in 2015 at age 79, and was a somewhat memorable character acted. However, much more famous is his daughter, Juliette Lewis. He had nine other children (!!), and a few others attempted acting, with some limited success.