A review of tonight's "You're the Worst" coming up just as soon as I flash Gnarls Barkley after that Fiona Apple show...

This has been a fall for TV episodes that open in a way that makes you wonder if your show accidentally got replaced with something else. The earthquake sequence at the start of "The Leftovers" season 2 and the movie outtakes from the "Fargo" premiere both seemed to come out of nowhere, serving as disorienting pathways into new seasons, even if they ultimately made thematic sense for both shows. "LCD Soundsystem" isn't quite as extreme a departure for "You're the Worst," in that Rob and Lexi literally live in the same neighborhood as Gretchen and Jimmy, and walk past Jimmy's house — and the mountain of empty liquor bottles in his recycling bins — within the episode's first few minutes. Still, the opening scenes almost make the episode feel like a backdoor pilot for a spin-off starring Justin Kirk and Tara Summers(*), about a Cool Couple so entrenched in their own hipsterism that he's in a band that includes a freaking theremin player.

(*) This sort of thing was common in '70s and '80s sitcoms, where you'd see Mike Brady or Cliff Huxtable saying hello to a brand-new character, who would then take over the rest of the episode.

But the episode has to commit to spending so much time with the newbies, not just to establish them well enough so Rob's turn in the final scene — from Gretchen's aspirational role model to sad, creepy guy walking just up to the precipice of hitting on her — will have the proper impact, but so that we can fully appreciate the level of Gretchen's obsession with them. Her world has suddenly become all about these two, so our time this week in "You're the Worst" world has to be about them, too.

It's a tricky thing to pull off, particularly since the newbies are the kind of characters whom the show would normally be mocking. Here, there's some attempt at nuance, particularly as we see the cracks starting to show in the beautiful facade that Gretchen has fallen in love with, but I still spent a fair amount of the episode rolling my eyes at them.

But my reaction to them is less important than Gretchen's, and Aya Cash sells the hell out of Gretchen's belief that Rob and Lexi represent a way forward, a path out of her current miserable life as a clinically depressed dirtbag with a job she doesn't enjoy and a boyfriend who thinks he can fix her. Check that blank expression as Jimmy talks to her like an adult in a Charlie Brown cartoon, and compare that to the pure elation on her face as she takes Sandwiches for a walk after dognapping him, and then to her ugly crying as she walks home after Rob has shattered her dreams. That's not only spectacular range by Cash, but impressively conveys how much of herself she has invested in this fantasy, to the point where she's stalking this family, arranging to carry the baby around a grocery store for a few minutes, and taking the dog altogether.

The kind of experimenting with both form and tone that we've seen in episodes like this and "There Is Not Currently A Problem" is the kind of thing a show needs real confidence to even try, let alone pull off. "You're the Worst" absolutely has it now.

Some other thoughts:

* While many current series save money by putting supporting actors on contracts where they don't appear in every episode, "You're the Worst" isn't one of them. Lindsay's just not in the episode because there wasn't an obvious way to work her into the story.

* I asked Stephen Falk whether show-within-a-show "Exemplify" had been given any more thought than just that title. He described it as, "Obscure procedural in its 3rd season. Made straight for Bluecube Streaming service, an offshoot of the popular Bluecube DVD kiosk." He was also kind enough to offer up loglines for some of those episodes:

* While last season was only 10 episodes, this year the order is for 13, so we still have a month of "Worst" to go.

What did everybody else think?

Alan Sepinwall has been reviewing television since the mid-'90s, first for Tony Soprano's hometown paper, The Star-Ledger, and now for HitFix. His new book, "TV (The Book)" about the 100 greatest shows of all time, is available now. He can be reached at sepinwall@hitfix.com