Hawaii Five-0 Season 9 Episode 15 Review: Ho'opio 'Ia E Ka Noho Ali'i A Ka Ua (Made Prisoner by the Reign of the Rain)

If filming in Hawaii, it makes perfect sense to use a natural disaster as a backdrop.

A hurricane was at the heart of Hawaii Five-0 Season 9 Episode 15.

The hurricane added a claustrophobic feel to the episode, with most of Five-0 trapped at the Iolani Palace along with a drug lord turned state's witness, and the assassin sent to kill him. A well-intentioned Tani wandered into a stash house.

Protecting a Serial Killer - Hawaii Five-0

Finally, Danny, Rachel, and Charlie spent a relatively quiet evening at home, reconnecting.

Let's visit with the extended Williams clan first, since that was the most realistic portion of the episode.

It's been hinted all season that Rachel is ready to leave her second husband behind so that she and Danny can become a thing again.

Family Gathering - Hawaii Five-0 Season 9 Episode 15

It appears that Danny's girlfriend disappeared sometime between seasons, so he's also free again.

Related: Hawaii Five-0 Season 9 Episode 14 Review: Depressed With The Heat of Kealwalua

Now that Grace has recovered enough from her injuries from Hawaii Five-0 Season 9 Episode 12, she's back on TV's longest college tour, I think.

That means that Danny and Rachel can play house again, with only the oblivious Charlie underfoot.

It was cute to watch them pick through a moldy box of memorabilia, with a stick deodorant setting off memories of their earlier times together.

It was like all the tension between them just flew away.

Why not put them back together? They've both matured, and Rachel discovered that being the trophy wife isn't all it's cracked up to be.

Danny kvetches like an 80-year-old Jewish man, but he does seem able to find his younger self around Rachel.

Related: Watch Hawaii Five-0 Onlne: Season 9 Episode 14

Besides, they still have another child to raise in Charlie, and wouldn't that be more easily accomplished if they were together?

And maybe we'll get a little more Scott Caan as a result. I doubt it, but maybe ...

And of course, McGarrett, only slightly the worse for wear, drops by to nose into Danny's business the next day.

I think he's living vicariously through Danny's rejuvenated relationship because who the hell knows at what international hotspot Catherine is currently?

 Most of the action was happening at the Iolani Palace, set up to be the perfect storm.

There were a couple of hundred civilians seeking refuge there, then a handful of FBI agents protecting a murderous state's witness and finally the assassin sent to kill El Diablo.

End of the Storm - Hawaii Five-0 Season 9 Episode 15

Talk about your unnatural disasters.

I felt worst for Jerry. Is he living in the basement? If not, why does he have so much stuff there? Shouldn't a computer wiz like himself appreciate the value of digitizing?

Related: Hawaii Five-0 Casts Joan Collins

It's a good thing Jerry was there however to solve the mystery of the assassin's identity with a glimpse at the killer's tattoo and access to a couple of databases.

How did procedurals even solve mysteries in an hour without computers? What's that? With shoe leather and good old-fashioned police work?

Finding the Mole - Hawaii Five-0 Season 9 Episode 15

Do you mean to tell me that with all the military bases on Hawaii, the only place the FBI could find to secure their high-value asset was the Palace, a place that couldn't be secured with all the civilians sheltering there?

Especially when their prisoner had such a reputation as an escape artist? Of course, the hurricane gave Vega a good reason to stay put there.

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Grover's gift of gab was put to good use keeping the young deputy awake after Jerry had tended to his stab wound with a first-aid kit and Web MD.

I would have liked a report on Haku, but I guess we have to assume he survived, unlike most of the FBI agents.

In a Tight Spot - Hawaii Five-0 Season 9 Episode 15

It's like those FBI vests were the new red shirts.

Of course, it all came down to McGarrett having a knockdown, drag-out fight with the younger assassin.

Alex O'Loughlin and/or his stuntman ought to be getting every third episode off instead, to recover from those at least monthly battles.

Then there was Tani, who manages to get in over her head about as often as Steve gets involved with hand-to-hand combat.

Warning Stragglers - Hawaii Five-0 Season 9 Episode 15

She made one stop too many on her safety checks.

At least Tani managed to outsmart a 6-year-old girl before taking down her parents, only to come up against three more thugs stopping by the stash house.

Tani did take out two of the gunmen armed only with attitude and one magazine.

But it was fortunate that Junior didn't do the sensible things and go back to the office, instead opting to look for her.

I'm still enjoying Tani as a character, but boy, does she step in it with regularly.

I'd like to think she'll learn, but it's too early to predict that.

To catch up on the season before next week's doubleheader, watch Hawaii Five-0 online.

Was the case of the week at all viable? When will Tani learn? Should Danny and Rachel get back together?

Comment below.

Dale McGarrigle is a staff writer for TV Fanatic. Follow him on Twitter.