HBO Max gave Stephen King fans quite the treat on Halloween, with the surprise drop of a new episode of IT:Welcome to Derry simply called A Story of Derry. Apparently the already upsetting tale of how the indigenous people of Maine locked Pennywise in his “cage” was missing a few ghoulish details. But is this half-hour horror tale worth the watch?

The Gist: A key part of IT: Welcome to Derry dug into how long the cosmic entity simply known as “It” had been terrorizing the area we know as Derry, Maine. Rose (Kimberly Guerrero) was our key source for It’s storied history and she explained how her people passed on stories warning children of “the Kollu” who preyed upon those foolish enough to enter the Western Woods. Well, apparently the version we got in IT: Welcome to Derry was the “Disney” version, cleaned up for kids.

A Story of Derry follows teens Necani (Kiawentiio), Kino (Isabel DeRoy-Olson), and Maneese (Michael Podemski-Bedard) as they break the rules and enter the Western Woods to hunt for more food there. Unfortunately, the Kollu is real — as is a high-as-a-kite warrior named Mitig (Zahn McClarnon) who has survived in the woods thanks to sporting a dagger he broke off of It’s initial cosmic prison. (It’s the same blade that sweet Lilly Bainbridge [Clara Stack] finds in IT: Welcome to Derry.) At first, it seems Mitig will protect the children, but then Maneese discovers that their protector has been sacrificing humans to It and living off their flesh. Horrified, the kids attack him and run off with his precious dagger.

We then get a more detailed breakdown of Necani’s mother Sesqui’s (Morningstar Angeline) fight against It and a very Stephen King-lore heavy explanation for how they figured out how to trap It in Derry. (Hint: it has to do with Maturin the Turtle god.)

What Movies Will It Remind You Of? Obviously, this is a spin-off — addition? — to IT: Welcome to Derry, but the episode’s eagerness to weave in direct Dark Tower world-building also evokes Mike Flanagan’s recent remix of Carrie for Prime Video.

Performance Worth Watching: Zahn McClarnon is a standout in anything he does, but here he’s allowed to shrug off his natural nobility in exchange for pure unfettered chaos. His Mitig is an absolutely unsettling performance because you never quite know if he’s good or evil; you do know he’s dangerous.

Our Take: I’m not entirely sure I needed a bonus thirty minute episode of IT: Welcome to Derry that doesn’t even give us Bill Skarsgård’s Pennywise, but A Story of Derry is so beautifully directed, so terrifically acted, and so efficient in its storytelling, I don’t care. Director Tazbah Chavez plays with color and light to make you simultaneously feel like we’re witnessing the golden era of Derry and its darkest chapter.

Stephen King obsessives will gobble up all of the references to Maturin and The Dark Tower, but even if you’re not plugged into each and every Easter egg, Zahn McClarnon’s performance alone makes this a must-watch spooky season watch.

Our Call: STREAM IT! Zahn McClarnon’s “Guest Actor in a TV Drama” Emmy nomination is officially locked up — and HBO is reminding everyone binging Carrie that they’re also key players in the Stephen King adaptation business. It: Welcome to Derry Season 2 is very much still happening!

Meghan O’Keefe is Senior Critic at Decider.