Spoilers follow for It: Welcome to Derry Episodes 1-5.

It: Welcome to Derry has been dancing on thin ice with the embellishments it’s making to Stephen King’s novel, and not just because “that’s not how it is in the book.” Adjusting the time period to align with Andy Muschietti’s feature adaptations? No big deal. But It: Welcome to Derry has taken significant liberties with the relatively straightforward historical interlude that forms the basis of this season’s narrative arc, not only magnifying the role of preexisting canon (like Dick Hallorann’s presence in Derry), but also folding in ideas or plot threads from other King fiction as a way to flesh out the world, the latter approach having provided the structural basis for Hulu’s Castle Rock series just a few years back. Welcome to Derry hasn’t been entirely consistent in alchemizing all of this reference material and influence, but when it works, it works.

With no better way to stress-test that alchemy than a trip into the sewers beneath Derry, “29 Neibolt Street” represents another significant collision of Welcome to Derry’s adaptations and inventions, doubling down on its own imagination to effective ends.

After Marge’s heinous encounter with It last week, which ended with her nearly carving out her own eye, reunion becomes a major theme of the kids’ storyline in “29 Neibolt Street.” Marge (Matilda Lawler) covers for the very guilty-looking Lilly (Clara Stack) after the attack and the two reconcile - nice, considering Lilly and Marge’s friendship feels like one of the more genuine relationships on the show - but far more relevant to events this week is the return of Matty Clements (Miles Ekhardt)... from the sewers. Recounting his last few weeks essentially being kept in Pennywise’s pantry as a fear snack to come back to later, Matty’s revelation that Phil Malkin’s still alive spurs the kids into undertaking a rescue mission to It’s lair to save him, giving Lilly a nice leader moment as she asks her friends to consider whether they’re “anchors or lifeboats” when the people they love need help.

General Shaw’s plan to “shrink the cage” around Pennywise by recovering the pillars, and the bridges he seems to be willing to burn with Rose (Kimberly Guerrero) to enact it, continue to baffle, but more and more that’s starting to feel like a problem with how the character is written rather than the actual mechanics of the Operation Precept plan itself. The idea that chunks of the comet It crashed to Earth imprisoned within could repel (or contain) Pennywise may be outside of the scope of the It novel, but the logic is straightforward enough and the best laid plans of military men often go awry in King stories anyway. James Remar has done great work keeping Shaw a likeable character, even as he does unlikeable things, but now that rubber is hitting the road and there’s an actual plan to go pillar hunting, he’s hinting at heel turns a little too quickly that feel incongruous to his measured nature. He’s even teeing up a failsafe plan for a town-wide “cleanup” should their mission fail that portends some harrowing conflicts to come. All I’ll say is this: I really noticed that “Arrowhead Hotel” sign in downtown Derry when the kids biked by it this week.

“29 Neibolt Street” gives us more of a window into Rose and her nephew Taniel’s (Joshua Odjick) close relationship as well, with the reveal that Taniel’s in line to become the “Keeper” of the ceremonial blade made from Pennywise’s comet (can we call it KrITonite?) It’s an archetypal role for Taniel which feels like a natural precedent for Mike Hanlon’s eventual decision to stand sentinel over the town after the Losers defeat Pennywise in their childhood. Is it a little silly that the knife glows for Pennywise like Sting glows for orcs in Lord of the Rings? Yeah, absolutely. But as we drive closer and closer to “The Augery” - a term Welcome to Derry introduces this week to codify the mass killing event that ends Pennywise’s feeding cycles - having these wild-card plot elements in play still feels like a gambit worth seeing through, especially after Lilly winds up barely surviving her encounter with Pennywise thanks to the knife’s ability to repel it.

Welcome to Derry throws another curveball into the kids’ trip into the sewers to save Phil: each of the kids takes three “Mommy’s Little Helpers,” the barbiturates Lilly stole from her mom in hopes of suppressing their fear and protecting them from Pennywise. This was a monster of a pharmaceutical Sword of Damocles to hang over the heads of children, and a big swing to take, but in practice the kids drugging themselves feels like a hat on a hat. The sewers are the most dangerous place in Derry to begin with, and Pennywise can already create illusory nightmares - we would have had to really lock into at least one of the kids’ specific and amplified perspectives for this flourish to land. Instead, the kids just get wobbly, slur their speech and see double. Pretty significant missed opportunity, but maybe Mommy’s Little Helpers will come back around again for some redemption later in the season.

The soldiers’ perspective in the sewer sequence benefits from some great atmosphere thanks to some body-mounted red lights and deep-yellow flashlight beams, but them getting picked off one by one doesn’t move the needle much, with the Uncle Sam “I want you” gag feeling just a little too cute. The chaos does force both Leroy Hanlon (Jovan Adepo) and Dick Hallorann (Chris Chalk) into reckoning with the true scope of the danger they’re in, though. Leroy may have been brought into Operation Precept for being a “man without fear”, but nearly shooting Will because he was afraid he was a monster and killing his best friend Russo (Rudy Mancuso) in the process is going to force him to confront that he may not be able to get through this mission on grit alone. Hallorann’s struggling too, with the oppressive psychic forces he’s faced with beneath Derry fueling some trauma that’s been coming to the surface over the last few episodes: his childhood living with his sadistic grandfather. Dick’s ability to suppress “ghosts” like his grandfather’s inside of mental lock boxes is a lovely bit of the character’s background established in Doctor Sleep to deploy here. Dick’s felt in control of most supernatural encounters he’s had up to this point, and Welcome to Derry visualizing that slipping control with something that’s rooted in King’s fiction felt like the perfect counterbalance to all the original lore with which the writers have been supplementing the story.

Welcome to Derry’s been holding back on Bill Skarsgård, and that has been to the series’ advantage. As a novel and as a film, It thrives as much on the looming danger and influence of Pennywise as it does on the monster’s actual chompy-chompies and rippy-rippies. But the time felt right, and right it was: with both the kids and the soldiers converging on the sewers, Pennywise floats out of the darkness - or to be more accurate, out of Matty Clements’ reanimated corpse - for dinner. Yes, the boy who wandered back to the Derry standpipe after being abducted by THE EATER OF WORLDS AND OF CHILDREN in the series premiere was Pennywise playing possum all along. The only false note of Skarsgård’s proper introduction here is the last beat of his emergence from Matty’s corpse, which puts a weird shimmering backlight behind him that makes him look like he’s just been revealed as a DLC fighter in Super Smash Bros. Ultimate (or, more appropriately given the WB of it all, MultiVersus). From a performance standpoint though? As chillingly cloying and confident wielding the clown’s disquieting rhythms as ever, Skarsgård hasn’t lost a step as Pennywise.

It’s a strength of “29 Neibolt Street” that everyone gets into the sewers as quickly as they do, but all that momentum leaves the developments in Hank’s storyline feeling a little tacked-on. Hank’s nearly killed by Phil and Susie Malkin’s dad while being put on the bus to Shawshank State Prison, an act of violence which mostly functions to give Charlotte Hanlon (Taylour Paige) reason to notice yet another Derry citizen - a cop this time - under the deep-seated influence of It. Charlotte’s mostly on the sidelines this week, considering her next moves, after Leroy makes the call to move her and Will onto the air base what with violence starting to flare up in town. After the prison bus is attacked by Pennywise (offscreen) and Hank gets free, we discover the identity of the mystery lover he flees to the home of: Ingrid Kersh (Madeleine Stowe), Lilly’s ally from Juniper Hill.

After watching her husband Stan, Derry’s butcher, get on her case for as minor a “transgression” as cooking his steak past medium-rare, Hank’s fear of he and Ingrid being found out feels justified. The racial undertones to the vitriol swirling around town are incredibly important for the show to keep teeing up, given where Constant Readers know we’re heading. But with no real connection to the more pressing events happening underground, Hank going on the lam is a drag on the pacing this week. The reveal that Hank’s lover and Lilly’s friend is Mrs. Kersh, though… that makes her motives when she doth things like protest too much against Lilly going into the sewers worth some second thought on the audience’s part from here on out.