NEW YORK (CNN) -- Director M. Night Shyamalan knows what scares moviegoers.
He did it as the writer and director of "The Sixth Sense."
He did it again as writer, director and producer of "Signs."
And now he's bringing the fear back once more as the writer, director and producer of "The Happening." (He also acts in the movie.)
Shyamalan sat down with CNN's Doug Ganley to discuss his latest thriller and why he calls it a B movie. The following is an edited version of the interview:
CNN: Why don't you go through the movie for us and tell us what the story is about?
M. Night Shyamalan: It's about a couple, actually played by Mark Wahlberg and Zooey Deschanel, and they're kind of having a little rocky moment in their marriage.
They think it's just a normal day for them, and an event happens in New York in the morning. An airborne chemical toxin was released in Central Park, and people are dying in a horrific manner, and they attribute it to terrorists.
And our couple starts to get scared, and they're only two hours away and they say, "Well, we should leave Philadelphia." So they leave, and just as they leave, it happens in Philadelphia, and then it happens in small towns, and then it happens everywhere around them.
They realize it becomes less and less likely that it's terrorists. And our couple find themselves in the middle of this area of the Northeast where this bizarre event is occurring, and they're basically trying to survive it.
The movie is really about ... this one moment. This moment of, if you realize that in 30 seconds you were gonna die, in a minute you were gonna die ... you're not fighting anymore ...it's over. You've given up that possibility. What will you say to your loved one in that last moment?
CNN: So a lot of people are going to see this and say, "Is this an environment movie?" Are you sending an Al Gore-like message out here, or is it just a thriller?
Shyamalan: No. 1, it's a B movie. This is the best B movie you will ever see, that's it. That's what this is. If there's other things that stick to your ribs as you walk out, that's great, but it's supposed to be, you know, zombies eating flesh.
CNN: So when you say B, you don't mean honeybee?
Shyamalan: No, I meant like, you know, zombies and killer things running around.
CNN: I've read in the press how you've been sort of inspired to write this story. Can you run us through that, too?
Shyamalan: Yeah. Usually getting an idea, like people say, "When did you get your idea?" and you say "I don't know." When did you get the idea is usually the most boring answer you could ever think of. "I just had lunch and then I just got the idea!" [laughs] But this one...
I was driving down the highway from Philly to New York, which is about a two-hour trip and the highway, the Pennsylvania Turnpike, you know, basically goes through farmland for a lot of the trip. And you're just seeing beautiful greenery for as long as you can see on either side and trees hovering over the highway and it's just going by the window.
And then I had the score going for movies, like this dark score, and the trees and dark score and said, "Oh my God, what if, what if it turned on us?"
CNN: This movie was shot at accelerated place. Did you try to do that on purpose to wrap up the intensity on set?
Shyamalan: Yeah, you know, it was great because it fights my instincts. I am more of a quiet, take your time kind of guy filmmaking-wise and this one was, you know, breathless from the second the movie starts to the end, so I had to kind of keep that energy up.
I mean, I told everybody when we started, this movie cannot be longer than 90 minutes. It needs to be a 90-minute movie. Very tight experience. And that required a lot of discipline on the way because normally I'd be like, "OK, let's take our time, the camera moves around me and finds you and then you say your line and. ..." You can't have that. Your characters are panicked. So we've got to keep that going through the movie. iReport.com: Share your review of "The Happening"
CNN: All your movies are very distinctive. Do you find it tough in the way Hollywood is set up today to keep your voice when you are making a film?
Shyamalan: Definitely. The system is not made for original [mumbles] movies. That's not the way the system is set up. It was set up that way before, but it is not that way right now. And hopefully it will go back to being that again.
But right now, I think people look to put you on a shelf somewhere, but my movies don't fit on the same shelf. They are all on different shelves. And only time, I think, will make that be OK, but right now sequels are God, um, so I am kind of God-less. [Laughs]
CNN: So is that why you stay in Philadelphia then? To sort of keep yourself outside of the. ...
Shyamalan: No, it's not so much as an agenda, as it is who I am. You know, I was raised in Philly. I was born in India ... and my parents moved to Philadelphia, and that's where I've stayed. And now I raise my family there.