Set in the eponymous Maine town, a creation of King's that he named after a location in William Golding's Lord of the Flies, the show is a fable of sorts about the stories we tell to absolve ourselves—about legacy and buried secrets and blind eyes. Showrunners Sam Shaw and Dustin Thomason created something quintessentially King. Castle Rock is not a mystery to be solved, but rather a meditation on the lack of resolution, and what that does to a person over time. Things wrap up, but not nicely.
The finale begins with a "previously on" montage that takes us back to Henry Deaver (André Holland) as a death row lawyer, preaching—not unlike his father—to the court about the morality of capital punishment. "How much doubt is reasonable?" he asks. "Well, folks, if I had to choose whether or not to take someone's life—and that is the choice before you today, make no mistake—I don't think any amount would seem reasonable. And me, if I had to kill someone? I'd need it etched in gold and signed by God himself."
The irony of Deaver's speech, as we later learn, is that he took a life himself, or at least attempted to. By episode's end, we finally learn the truth about the day Henry Deaver disappeared. He pushed his hysterically evangelical father off an icy cliff to prevent the man from killing his mother, Ruth (Sissy Spacek), which he planned to do after learning of her affair with Alan Pangburn (Scott Glenn).
"For the wages of sin is death," the elder Deaver says, quoting the book of Romans. Though Henry's push didn't kill his father—Molly Strand (Melanie Lynskey) later finished him off—the act was implicit. Henry Deaver would dedicate his life to saving lives, even guilty lives, as some sort of repentance for the act. Like all of King's heroes, he's a complicated, burdened man with a lifelong debt to pay.
Henry's hatred of his father culminates in another of the finale's big moments. Viewers have been fascinated with the identity of the mysterious "Kid" (Bill Skarsgård) who showed up in an underground cell at Shawshank Prison in the pilot. Just last week, The Kid's true identity was revealed: He's the Henry Deaver of another universe, a universe where the Deavers didn't lose a baby son; the woods of Castle Rock contains an effervescent portal to other worlds.
Because the other Henry is not a part of this specific timeline, he appears ageless, and disrupts the fabric of reality around him; people touch him and go insane, death and decay follows him, birds gather in odd formations as he walks the streets. He is the source (or at least one) of Castle Rock's painful history. A thing out of time, place, and reality whose presence creates something anarchic.
The Kid tells the Henry of our world his story, knowing that if anyone might believe him, it would be his otherworldly counterpart. Henry himself was once a similar prisoner in the other world; that's where he disappeared to, and where he stayed for almost 30 years, which translated to just 11 days on the other side. Surely Henry could have compassion for this man who's suffered so much, in such a similar fashion?
But our Henry doesn't remember what happened to him 27 years ago. He is haunted less by his time in another world and more by his time here, and the guilt he carries about his father. He looks at The Kid and sees only his father's manic fantasy talk. The Kid begs Henry to take him to the woods, where he assumes—thanks to the loud humming there, which gets louder every day, and might indicates a weakening in the dimensional fabric—he can return home. But the language The Kid uses ("I don't want to hurt you, Henry") is nearly identical to what Henry's dad said to him all those years ago, and it triggers something: rage. Henry turns on the kid as the police envelop them. We cut to one year later. The Kid is returned to his cell under Shawshank, where Henry visits him.
"After a while you forget which side of the bars you're on," The Kid says from his prison. He tells Henry that that's what Warden Lacy (Terry O'Quinn) used to say to him, after he captured The Kid and put him in the same situation. Lacy eventually killed himself. Will Henry suffer the same fate, now that he's chosen this life of guilt, a life where he chooses to actively disbelieve?
Castle Rock doesn't tidy up every answer. We never learn what compelled Lacy to assume The Kid was the devil, or why he locked him up 27 years prior. We get a quick glimpse of The Kid as something evil, when his face briefly flashes to that of an aged, monstrous figure. Is he really the Henry Deaver from over there, or is he something else? And did Henry make the right choice in putting him away again?
We'll never know. This story is over now, as Castle Rock will be told in anthology format. But the ending is still enormously satisfying in that it doesn't bend over backwards to surprise us. It recalls the ending of so many Stephen King stories, where the bittersweet is absolute. This isn't a show about a place, and about the people who live there, who are fallible to human whims. Letting the devil out, then putting him back where he came from without ever learning what he's all about—that sounds like the plot of King short story, nestled in a tome of other horrors. It's fun to think of Castle Rock the way you'd think of a King collection like Different Seasons or Full Dark, No Stars. Many tales in one place, waiting to frighten you. Bring on season two.