What's a father to do when his daughter from 21 years into the future suddenly appears in the present? Get into fights with the Russian mob, of course. This sounds more like a Flash plotline. Actually it kinda is. But with Arrow, it somehow feels more organic. The adult children cast has some natural chemistry with the modern-day cast, and it all fits in with the end-of-the-world weirdness. This week, Oliver and his Future Kids travel to Russia. Spoilers follow for Arrow, season 8, episode 5, "Prochnost."

"Prochnost"

I've been consistently surprised at just how well Arrow's "farewell tour" season has been using all of the character equity it has built up over the years to bring us some genuinely surprising, compelling, and even heartwarming interactions between characters who often have never met.

Oliver worries the Monitor is not who he says he is. He wants to build a weapon that can take the interdimensional being out if he should reveal himself to be anything other than well-intentioned. That sends John Diggle off looking for plutonium and Oliver heading to Russia for plans. While John has an idea of someone to recruit, Oliver takes his adult children and Earth-2's Canary, Laurel, with him.

Any trip to Russia would be incomplete without a visit to Anatoly, of course, and Anatoly does not disappoint. He's been one of my favorite characters since the beginning, even when he betrayed Oliver a couple of seasons back. There's a simple calmness to his demeanor, and it's so rare that he feels like he's hiding something. When he offers Oliver guidance, it is often simple and straightforward.

Return to Russia

This episode offers a great whirlwind revisiting of his time in Russia filtered through the eyes of his naive daughter. Mia, having grown up without her father present, has a serious case of hero-worship that informs how she views the modern-day members of Team Arrow, and this forms the basis for some of the episode's best moments.

First, though, Oliver has to get his head on straight. Every time Oliver makes a new connection, his first instinct is to isolate that new connection from all the dangerous or difficult parts of his past and life. He does that immediately with Mia and William. His excuse is that he doesn't want to endanger his children for Felicity's sake, but Anatoly reels him in. He's really trying to protect himself from having to tell his kids about some of the bad stuff he did before becoming a hero.

Oliver's reticence ends up with both he and Mia captured, and Mia gets a crash course in Oliver's life. The two are held at gunpoint. Then, Mia is forced to do the bell-ringing gauntlet that Oliver had to complete to join the Bratva, which involves getting past a series of men and ringing the bell within a minute. Oh, and she cringes appropriately when Oliver dislocates his thumbs to get out of his bindings.

Mia and Laurel make a great team

While Oliver tries to push Mia and William back, Mia ends up having a conversation with Laurel, and again, these two have great chemistry because of the different places they're coming from. Laurel used to be Black Siren, and Black Siren was bad to the bone. And then slowly but surely, Team Arrow changed her mind. But she still doubts herself. There's a bad core in there that could resurface at any time, so why resist?

Mia comes from the future, though, where Laurel is a legendary hero and someone who has even saved Mia's bacon once or twice. In Mia's eyes, Laurel is the epitome of a hero. Laurel and Oliver are legends of yesterday for her, and she doubts herself because she can't measure up to their perfection. This scene was nearly a tearjerker for me because the things these two characters have to teach each other are so realistic and so well-earned for them. The look of surprise on Laurel's face when Mia tells her about the heroic Black Canary of the future speaks well of actress Katie Cassidy's acting chops. Not to mention how the show literally killed one version of her off and then brought this new one in - and how different the two feel.

Legends of Yesterday

Mia, meanwhile, is having to wake up very quickly to the fact that these legends are actually humans, and that they made mistakes and that she gets to make mistakes. She doesn't know that Laurel was a literal villain in her past life, nor that her father had to do some shady stuff. She has to come to grips with that even as Oliver accepts that he has to let her into that.

These moments are surprisingly powerful and wouldn't be nearly as effective if the show hadn't spent time developing all of these people. So much of what Arrow has done since 2012 is being used effectively here, and it's paying off.

While that's happening, John stops by a car shop asking for Jason. Out from under a car slides Roy Harper, who had disappeared last season after having difficulty controlling his Lazarus-fueled bloodlust. Roy has been isolating himself, and Diggle works hard to convince Roy that the best way to resist that urge is to surround himself with people he trusts - a team. While I'm not sure that exposing him to violence on the daily is super smart, this echoes the struggle that Oliver has been going through for years and has to continue to push back against. Once you learn to isolate yourself, it's hard to unlearn that.

I enjoyed seeing Diggle act as a sort of big-brother figure for Roy as he has so often for other members of the team, and to have Roy pulled back into the fold for the last few episodes of the series.

Betrayal

The final few minutes of the episode return us back to Laurel's conflict. Laurel proves herself reliable, impressing Anatoly; she seems more confident than ever that doing the right thing is, well, the right thing for her. That culminates in a meeting with Lyla Michaels, who is working with the Monitor. Laurel turns down the Monitor's request that she betray Oliver, and then summons both him and Diggle out of the shadows. Lyla's secret is out. And then, all three are shot in the neck with knock-out darts.

It'll be really interesting to see how this betrayal goes down. Who shot those darts? It's weird that Laurel's reaction was off-screen, too. I had to rewind to make sure she actually got hit with a dart because the show focused so much on Oliver and Diggle's. Could that suggest that she's up to something? I hope not. Her growing confidence has been a bright point in an already enjoyable season.

I still can hardly believe that this show exists in the first place, but I'm glad it does because Arrow season 8 is a blast.