I always enjoy reading Mike's thorough reviews, so I decided to wait regarding commenting on the episode until he posted one.
First, go read Mike's review, for synopsis of the story and a good analysis of many of the episode's problems: http://www.fiveohomepage.com/2010-log10.htm#5
While I agree with Mike that the Halloween episodes are getting tiresome, I liked last year's version a lot better than this one (even though some people, including my own father, hated the 2018 edition).
The episode began with what appeared to be a typical cold open, of a previously-unknown (and usually cheerful) character going about their day normally, before either getting murdered or discovering a body. In this case, a nice older lady seemingly living alone was murdered on Halloween (she answered the door expecting more trick-or-treaters), abruptly shot dead by two male intruders dressed in black and wearing masks. They were quickly shown to be after a large vault in one of her rooms, where they expected money or valuables to be stored. However, upon breaking into the vault, there were no valuables, but rather a humanoid-looking monster locked away, who proceeded to attack and quickly kill one of them, with the other running away terrified.
As far as I remember, this was the first Five-Zero cold open where one of the "victims" of a killing had just murdered someone else!
Right when this occurred, a thought immediately entered my mind. "Clearly this monster is going to end up a sympathetic character, and that's why they had him kill a really bad guy, so the viewer wouldn't hold that against him."
Indeed, that ended up being the case. The "monster", who turned out to be a deformed man, hidden away for over 30 years by his former-nun adoptive mother (the woman who was murdered), was simply misunderstood and suffering from the psychological damage resulting from being locked away nearly his whole life.
The entire mystery of the "monster", who was briefly hinted at "possibly not being human", was not very interesting. While Five-Zero always flirts with the suggestion of the supernatural in its Halloween episodes, there always ends up being a logical earthly explanation for everything that has happened. Reminds me a bit of "Scooby Doo"! The segments of the show involving solving the mystery of the vault monster were leading to the obvious conclusion -- that he would be found and shown to be a misunderstood, deformed human adult. I will concede that the final scene, where he was reunited with his birth mom, was touching, and probably one of the better done "emotional Five-Zero scenes" I've seen in awhile.
The other crime of the week was weird, and not particularly well written, as Mike pointed out several times in his review. I was completely confused by its climax, where the third murderer of "Lana" was hit on the head by an Asian woman while trying to dispose of the body, and he said "Lana? But how?" before being knocked out cold. Briefly, I thought the body of "Lana" (whose identity was assumed but never fully verified) was actually still alive, and it was her sister Emily who had been murdered. But no... it turned out Lana really was Lana, and Emily was indeed the one knocking out (and attempting to drown) her sister's murderer. Confused yet? I sure was. No idea why the writers inserted that whole thing, in what was already a difficult-to-follow storyline. Also, as Mike pointed out, it was never explained how Emily found the guy dumping Lana's body in a remote location.
Didn't love all the usual Halloween Ohana crap, though they kept those scenes moving without dragging too long. Once again they dressed Tani in a skimpy outfit in attempt to show off her body.
The most curious thing about this episode was the return of Max. He brought home with him an adopted son from Madagascar, though it's not explained how he came to adopt this child, or whether or not Max is staying in Hawaii. It's hinted that Max will be seen in future episodes, as he stated several times that he "missed all of this", despite finding his work in Madagascar to be rewarding.
Actor Masi Oka has done little of note since leaving Five-Zero in early 2017, so perhaps he decided to return to the series after finding little work elsewhere. He wouldn't be the first actor to leave a long-running TV series for greener pastures, only to come crawling back after not being able to do any better. I always felt that the Max character was mostly there to pander to the geek contingent of the Five-Zero audience, and I found it annoying. Nearly episode he appeared in was some form of, "Hey look, geeks, we totally get you", aside from the one very good episode about his murdered mom.
If Max does return, what will happen to Noelani, who replaced him? I liked her character a lot better, even though it was a bit boring. At least she wasn't annoying.
Mike gave this episode two stars, which is probably what it deserved.