At first blush, horror is a genre that wouldn't seem to lend itself well to television. So much of what makes a scary story effective in a darkened movie theater shouldn't necessarily apply to a weekly series. You can maintain a sense of dread, or willingly suspend your disbelief about why the damn fools won't get out of the haunted house already, for two hours, but week after week for years? That's tougher.

But horror has had some past success on the small screen ("The X-Files," for instance, took more of its stylistic cues from horror than science-fiction), and we're in a mini-boom right now with AMC's "The Walking Dead" and FX's "American Horror Story." You can argue with how successfully each of those shows has tried to tell their ongoing stories — and even the "AHS" producers recognized they couldn't keep their story going past a single season, and will start over from scratch with a new idea and characters — but these are very big hits for their respective channels, and "Walking Dead" has a long-running comic book series to draw stories from for years to come.

And now comes "The River," the new ABC found-footage horror series from "Paranormal Activity" creator Oren Peli, which is debuting tomorrow night at 9. I watched the pilot months ago, was impressed by the level of suspense maintained throughout, yet wondered how on earth it would work as an ongoing series.

And having seen four additional hours since then (one of which will air after the pilot tomorrow night), I'm pleased to tell you that —for now, at least — it does work.

"The River," like Peli's films, "The Blair Witch Project," etc., uses a fake documentary format to present its story, in which beloved globe-trotting scientist and TV host Emmet Cole (Bruce Greenwood) goes missing in an uncharted stretch of the Amazon, and a team headed by his wife Tess (Leslie Hope) and son Lincoln (Joe Anderson) go looking for him. Cole's abandoned ship the Magus is practically covered from bow to stern with cameras, and the search is being bankrolled by Cole's old network and former producer Clark (Paul Blackthorne), who's filming the whole thing as its own reality show.

What initially seems like a simple disappearance in remote, unforgiving terrain is quickly revealed to be far more ominous, as the stretch of the Amazon where Cole disappeared is home to all manners of monsters, ghosts and other bits of local folklore that prove to be completely, terrifyingly real.

The amoral attitudes of Clark and chief cameraman A.J. (Shaun Parkes) add a layer of tension to even the most routine moments — like any effective reality show producer, Clark is continually trying to generate his own storylines through careful questioning and agitating — but the found-footage format also works perfectly here because a TV show doesn't have the budget or production time that a feature film does. The scares here have to be brief, and often barely alluded to — an unexpected figure popping up in the corner of the frame, a monstrous pursuer barely glimpsed because the people holding the cameras are running away from it — and the work of pilot director Jaume Collet-Serra ("Unknown") and those who follow very effectively exploits what the cameras do and don't capture.

Because Peli has no television experience, veteran TV producers Michael Green (the mind behind NBC's smart but short-lived "Kings") and Zack Estrin were brought in to make "The River" work as a weekly series. What they've done — somewhat impressively, given how limited the premise seems — is to borrow "The X-Files" storytelling model. There's the larger search for Emmet Cole, and that's never forgotten, but the river keeps throwing various supernatural obstacles in front of the Magus, each of which has to be understood and solved on its own. This is essentially what "Fringe" tried to do in its early years, pairing an ongoing narrative with a kind of sci-fi procedural format, but the Monster of the Week episodes wound up being much less interesting than the hours that answered bigger questions. In the early going, "The River" manages to make its various monsters at least as compelling as waiting to find out what happened to Emmet.

The show isn't perfect. As prodigal son Lincoln, Joe Anderson comes across as much more petulant and irritating than I think is intended. (The show is always on stronger footing when the stories revolve around Hope as Tess, or around Eloise Mumford as the daughter of Emmet's missing cameraman.) And the writing pushes the "reality TV producers are sociopaths" theme so hard at times that I'm shocked they didn't ask Blackthorne to grow the mustache he wears from time to time when cast as a two-dimensional English bad guy.

Also, the show's use of the two Spanish-speaking crew members — mechanic Emilio (Daniel Zacapa), and, especially, his daughter Jahel (Paulina Gaitán), who's like an encyclopedia of every local superstition that's coming to life for the Magus — is clumsy at best, ethnic caricature at worst. (It wasn't until the fifth episode before Jahel had a real conversation with anyone that wasn't related to magic in some way.)

But the series' embrace of its narrative style, its creation of such an ominous world and its skill for generating suspense practically out of thin air are all very impressive. And if Anderson is annoying(*), he's surrounded by a good mix of actors, including Hope, Mumford, Greenwood (seen frequently in archival footage of Emmet in happier times) and (as a shady mercenary protecting the Coles) Thomas Kretschmann. And in fairness, sometimes characters in horror stories have to be annoying and/or walking plot devices in order to make the story make any sense at all.

(*) Though I should note that while I usually don't care about hairstyles or costume choices on TV, Lincoln becomes notably less annoying after getting a short haircut in the third episode. Coincidence? Better writing? Or was his hair in the pilot just that stupid?

If the show is a big hit, can Green, Estrin and Peli extend the search for Emmet indefinitely and still keep things interesting? I have no idea, but these early episodes are entertaining enough — and did enough to quash my earlier skepticism — that I'm happy to ride along with the Magus for a while.

Alan Sepinwall may be reached at sepinwall@hitfix.com