Two years ago, Netflix’s “The Haunting of Hill House” was the most pleasant of surprises — though perhaps “pleasant” is not the word. The series was often terrifying, thanks in part to strong pacing, performances that worked across the board and a willingness to wear an unusual ambition and intellect proudly. Horror on TV was not new: The show, a closed-ended limited series, existed within a context established by Ryan Murphy’s “American Horror Story” earlier in the decade. But that show is rooted in a vampy, campy sensibility and, distractable in its broadness, has often lost its way. “The Haunting” was different. Methodically built using the work of novelist Shirley Jackson and willing to flaunt its intellect as well as its jumps in time, Mike Flanagan’s TV series — released before his high-profile leap to elevated multiplex material with 2019’s “Doctor Sleep” — seemed proof positive that there was a path for genre fare beyond Murphy’s venerable franchise.

That makes “The Haunting of Bly Manor” a somewhat deflating disappointment. The follow-up series, which shares with its predecessor a sensibility, a high-flying literary inspiration (the work of Henry James this time), a crisp and pristine visual aesthetic and some cast members, never takes flight in the way genre devotees might expect. For one thing, it’s too rarely really scary; for another, more important one, it gets confounded by its own story, doing something that’s less like toggling between corners of a complicated tale and more like losing threads. By the time the series concludes, after some nine hours, it’s fair to wonder what, exactly, the journey had been for.

Which is not exactly Jamesian! The master novelist was not one to use an extraneous word, character or moment; “The Haunting of Bly Manor,” lacking his precision, is instead spreading and sprawling. The story starts off in the U.K. in 1987, as an American expat (Victoria Pedretti) pleads with the lord of a local manor (Henry Thomas) for a job caring for his orphaned niece and nephew. These two unfortunate souls, who find in Pedretti’s character an eager and solicitous au pair, are played by Amelie Bea Smith and Benjamin Evan Ainsworth; the two child performers have mastered the art of sweet-natured mischief, explaining away their chaos as the stuff of children even when it seems to originate from a deeper and more sinister wellspring.

So far, so familiar: This is the plot of the novella “The Turn of the Screw,” and Flanagan carries it across elegantly. But his decision to draw upon various other James works, building out a series that ranges centuries into the past to explain the house’s bad vibes and plumbs the disparate traumas of other of the manor’s residents, yields diminishing returns. The further we get from what had been the show’s center, the less a center is apparent at all.

Why is this a problem, when “Hill House” also roved between its family members and skipped back and forth in time? Perhaps it’s the nature of the house’s curse, which has certain members living through a nightmare whose horrific power is its repetitious blandness. T’Nia Miller, who plays the housekeeper of Bly Manor (and was a standout on the remarkable limited series “Years and Years,” a horror story of a different sort) is well equipped to play the terminal, painful boredom and loneliness of being stuck in time, but she could do a lot more too. Sometimes the show jars less for structural issues than for jangling, underwritten lines. “I understand death. I know what loss is,” Pedretti’s nanny declares flatly in her job interview. Later, speaking to one of her young charges, she declares, “I’ve lost people a few ways in my life.” By the time we get around to excavating her trauma, it’s been so showily, cryptically teased that it would feel like an anticlimax no matter what.

Pedretti, such a revelation in “Hill House,” is misplaced this time around; that she’s left behind is the consequence of a show that can’t quite get a bead on what it wants to be. Bundling together James’ stories is a theoretically laudable goal as long as you don’t consider that stories are self-contained for a reason: They possess themes and elements that would take meaningful effort and great good luck to merge. Flanagan did not get lucky this time, and this second “Haunting” series looks less like the alternative it might have been and more like “American Horror Story”: a show with a lot to recommend it but precious little in the way of cohesion.