"The Case of the Missing Lifeguard" takes a thematically darker turn from the previous two chapters' more playful tone. Joyce and Hopper's somber trip back to Hawkins Laboratory gives us one more heartbreaking look at Bob Newby before he is torn to shreds by Demodogs. David Harbour and Winona Ryder are pitch-perfect in the scene where Hopper tells Joyce that all he wants for her is to feel safe in Hawkins. Even before their journey to the lab begins, it's hilarious to watch Hopper's jealousy towards Mr. Clarke outwardly erupt - especially when it's clear that Joyce has no interest in poor nerdy Scott beyond finding out what's up with her darn magnets.Back at the lab, we finally get to see that hulking, mysterious Russian take on Hopper, and while the confrontation between the two men is thrilling, the scene feels like the appetizer before a bigger potential showdown in a future episode. Andrey Ivchenko's Grigori has the perfect '80s action movie look, almost as if Arnold Schwarzenegger's body double stepped off the set of the first Terminator film. In a world where telekinetic abilities and scary monsters from different dimensions are commonplace, it's nice to see a good old fist fight once in a while.Poor Will Byers (Noah Schnapp) also has a rough go of things in this episode. Apart from Eleven, Will has gone through the most tumultuous journey, so who can blame him for wanting to be a little kid for just a few more months? Will and Mike's intense conversation about the ramifications of growing up is compelling, but also sad. The Duffer brothers are finding impactful ways this season to highlight the tragic nature of the kids' life-and-death predicament. It also appears that Will's connection to the Mind Flayer is still strong. Does Will's reaching for the back of his neck remind you of Harry Potter reaching for his scar every time he senses Voldemort?Stranger Things Season 3 GalleryBilly's arc gets more interesting after Max and Eleven discover him at Heather's house during a peculiar dinner with her parents. Dacre Montgomery plays the overly ingratiating house guest well - equal parts charming and creepy. The most fascinating reveal from the scene happens after Eleven and Max leave. Here, we see Billy\/the Mind Flayer remembering the events at the end of Season 2 after Eleven closes the portal. So is Billy building an army for his evil master, or is there something else afoot?In an episode filled with tragic stories, it's nice to know that we can always rely on Steve and Dustin's shenanigans to make us laugh. Their "find the Russian" mission at the mall is amusing, especially after the duo discovers that their primary suspect is the local Jazzercise instructor. The way the kids' adventures are structured in Season 3 makes Hawkins feel like a bigger place, and it's been fun to explore all of the new locations.Nancy and Jonathan's arc, however relevant, is the least interesting plot to follow so far. And even though it sucks to see Nancy getting picked on at work, she and Jonathan's Holmes-and-Watson routine isn't quite as captivating as the rest of Hawkins' storylines. Presumably, their investigation will enable them to cross paths with other characters, but for now, they feel a bit out of place in what is otherwise a great narrative.