Elliot (Mark Wahlberg, right) watches news of a mysterious neurotoxin attack with Jess (Ashlyn Sanchez, left) and her father Julian (John Leguizamo) in M. Night Shyamalan's The Happening. (Zade Rosenthal/Twentieth Century Fox)Remember when M. Night Shyamalan made good movies? You know, well-plotted, genuinely suspenseful thrillers like Signs and The Sixth Sense, the kind of films that receive Oscar nominations? These days, the former Hollywood wunderkind seems to be bucking for a different kind of award. The writer-director’s last picture, 2006’s soggy fantasy The Lady in the Water, won him a couple of Golden Raspberries. And if there’s any justice, he’ll get a whole bushel of them for his latest one, The Happening, which serves up the kind of half-baked sci-fi/horror scenario that even Ed Wood might have disowned. “Laughable” doesn’t begin to describe it; if Shyamalan is smart, he’ll claim it was intended as self-parody.

The premise of your average Shyamalan film is always rather sketchy, but in The Happening, it’s a total crock. Airborne neurotoxins, apparently transmitted by plants and trees, begin afflicting human beings, causing them to stop dead in their tracks, become disoriented and then promptly commit suicide. What ensues is a veritable orgy of self-slaughter. Cops shoot themselves with their own guns; landscapers lie down in front of running lawnmowers; zookeepers take a little stroll into the lion enclosure. I’m not giving away any grisly surprises – this all happens early in the film, leaving you to wonder what Shyamalan will do for the remaining 60-odd minutes.

Not much. You get the impression he thought this was a cool idea, but then only made a half-hearted attempt to flesh it out. The opening sequences, in which the toxin epidemic starts in New York’s Central Park, turn out to be the most effective part of the movie. There’s one scene in which a bunch of Manhattan construction workers on a break see a colleague plummet from the top of their building with a bone-shattering thud. Horrified, they run to help him. Then another body comes crashing down. And another. It’s a real-life construction-site nightmare transformed into the stuff of cinematic horror – truly chilling. But the chill wears off fast and soon all these mindless acts of suicide become a bad joke.

The toxin rapidly sweeps across the northeastern U.S., fueling speculation of an anthrax-type terrorist attack. People begin to panic. In Philadelphia, high school science teacher Elliot Moore (Mark Wahlberg) grabs his wife, Alma (Zooey Deschanel), and boards a train out of town, along with fellow teacher Julian (John Leguizamo) and Julian’s eight-year-old daughter, Jess (Ashlyn Sanchez). After the train strands them in small-town Pennsylvania – the drivers, unable to make contact with stations down the line, refuse to go on – Julian hitches a ride to Princeton to locate his missing wife. He leaves Jess in the care of Elliot and Alma.

A wave of suicides erupts across the northeastern U.S. in The Happening. (Zade Rosenthal/Twentieth Century Fox) The young couple, whose marriage has hit a rough patch (Alma has been tentatively experimenting with infidelity), strike off into the countryside with the little girl in tow, trying to outrace the plague. “Let’s just stay ahead of the wind,” barks Wahlberg’s wholesome Elliot, sounding like a Scout master leading a hike. Wahlberg, a likable actor, is amusingly retro in his early scenes; with his crew cut and sweater vest, he looks like he belongs in an Archie comic book. But for a science nerd, he doesn’t prove especially resourceful at battling this scientific threat. Nor does he strike any sparks with Deschanel – then again, her dozy Alma doesn’t give him much to respond to. The sapphire-eyed Deschanel is an attractive gamine – she could play the Chantal Goya role in an American remake of Masculine Feminine – but she gives a strangely clueless performance. “Close the windows and the doors!” cries Elliot when they hide out in a farmhouse. “Why?” Alma asks him blankly. Duh, it’s an airborne toxin, remember?

But let’s not blame the actors for inane dialogue that even George Lucas at his Revenge of the Sith nadir would be hard-pressed to match. Every time Shyamalan tries to inject a little quirky humour, à la Signs, his efforts fall flat; but when he wants us to take something seriously, it’s frequently hilarious. Then there are those times where you’re not sure what he’s trying to do. On the run, Elliot, Alma and Jess arrive at the isolated home of an eccentric old sourpuss (Betty Buckley), who grudgingly takes them in but then behaves like some psycho termagant. It’s hard to know what to make of her. Alma calls her “Exorcist-y;” I thought maybe they’d stumbled upon Norman Bates’s mother, alive and well and living in rural Pennsylvania.

Jesse (Ashlyn Sanchez, left), Alma (Zooey Deschanel) and Eliot (Mark Wahlberg) take refuge in the countryside in The Happening. (Zade Rosenthal/Twentieth Century Fox)Shyamalan brings all his familiar ingredients to the mix, but none of them gel. There’s the little kid to give an added sense of vulnerability; but Sanchez’s glum Jess is nowhere near as affecting as Rory Culkin (Signs) or Haley Joel Osment (The Sixth Sense). There’s the eerie Bernard Herrmann-style string music of composer James Newton Howard; but here, Shyamalan uses it like a bludgeon. (Sorry, Night; no matter how much you pump up the volume, it doesn’t make a scene any scarier.) Finally, there’s the famous Shyamalan twist at the end – sort of. It took me a few minutes to realize that’s what it was supposed to be. Is it possible to have a predictable twist?

The Happening is being touted as Shyamalan’s first R-rated film, a classification it no doubt earned for a few of its gory suicides. Yet it’s not as much bloody fun as a camp horror flick like, say, Cabin Fever – also a movie with a plague premise, but one that was actually more creepy and credible. Who knows, maybe Shyamalan was going for camp here, too, and he just doesn’t know how to do it properly. And I’d like to think he’s joking when he belatedly turns his film into a cautionary tale about our mismanagement of the environment. Why leave it at that? Why not say it’s an allegory, too – after all, you could argue that humanity is committing collective suicide with its toxic ways. Yet somehow I don’t see Al Gore endorsing this movie. If there’s an inconvenient truth here, it’s that Shyamalan is a vastly overrated filmmaker.

The Happening opens across Canada on June 13.

Martin Morrow writes about the arts for CBCNews.ca.