The movie opens with Wendy, a high school graduate from McKinley High, photographing her friends on a ride called the "High Dive". Shortly after she takes their picture, she notices the letter "V" missing out of the ride name, but thinks nothing of it. As the beginning of the movie progresses, we're introduced to several characters, including Wendy's boyfriend Jason, her best friend Tiffany, and her boyfriend Kevin, as well as other characters like the jock-like Lewis, the valley-girlesque Ashley and Ashlynn, and the goth-liking Ian and Erin., as well as Wendy's attitude-laden sister Julie and the troublesome "playa" Frankie. They all begin to make their way to the roller coaster, which has a demon-like figure at the front and a dark, foreboding voice warning them of the ride ahead. This begins to get Wendy nervous, even as she's taking pictures for the yearbook of everyone.
The group begins boarding onto the roller coaster, with Jason getting divided from everyone else, as he sits in the front car and the others sit in the back. Lewis is attended to by the ride attendant to adjust his shoulder pads, and this sets off a slight leak in a hydraulic pipe on the car, unnoticed by staff. Frankie hides a video camera in his pocket as Wendy's camera is pocketed by Kevin, sitting next to her. The ride begins and soon turmoil erupts as the leak continues and Frankie's camera is knocked away by Ashley, wrapping itself around the track. It's run over, causing the leak to become worse and the ride's shoulder belts to become loosened. One car suddenly jars entirely off the track, and others begin dropping off left and right. The ride suddenly stops upside down, forcing Ian and Erin to hang and eventually fall to their deaths. Kevin and Wendy motion the ride to go backward, but in doing so, Kevin is cut in half and Wendy is dumped onto the track...
Then Wendy wakes up and realizes it is all a premonition. She's still sitting in the car as it gets ready to move. She makes a big fuss and demands to be let off, and the attendant releases all the seats in the rear car. Wendy and Kevin exit, and soon the others follow, out of curiosity (and because Lewis almost strikes a fight with Kevin). Jason asks to be let off as well, but the ride continues with him and the people in the front car still sitting in it. Attendees lead a terribly upset Wendy outside and start to ask her details, and the coaster crashes, as predicted, leading to the death of Jason.
A little while later, Wendy is at the school and is confronted by Kevin, concerned about her and the loss of Jason and Tiffany. Wendy insists to be left alone. Ashley and Ashlynn invite her to a tanning session, and she takes their phone number. As she makes her way to her car, Kevin explains that this has happened before, with flight 180 and the seven people who got off...and died in mysterious ways. Wendy charges off as thunder booms overhead.
Ashley and Ashlynn head over to their favorite tanning salon, hoping to bronze up for a party. They both have Big Gulps, and the owner insists they trash them, as he heads off to complete a phone call. Ashley only pretends though, and they both head back to a tanning booth, where they proceed to disrobe. Ashley sets her drink down on a bench, right above a cooling unit for the tanning units. The girls also reach for a CD, knocking a book shelf slightly loose on one side. The owner heads out the door, with only a tube of lotion holding it open. However, the lotion squirts out, and the door closes shut and locks.
Meanwhile, Wendy is looking over the photos she took after she promises Julie the camera, and after Julie lent her a good friend bracelet left behind as a family heirloom. It's here she notices a photo of Jason with a foreshadowing of the coaster behind him, and gets an eerie feeling as the light bulb dims in and out. She finds Ashley and Ashlynn's number and proceeds to dial.
Back at the tanning salon, Ashley's Big Gulp has begun to leave a water residue, which leaks into the cooling unit and forces the temperature to rise slightly. As the girls seem to notice this, a cooling unit kicks in that causes a coat rack to tip.slightly. A vibration from the phone (Wendy's call) forces the coat rack to fall over entirely, causing a plant to fall on the book shelf and collapse. The panel from the self slides right into place on both units, locking both Ashley and Ashlynn in as the temperature rises. Both girls wince and scream in pain as the bulbs begin breaking, and soon a fire breaks out, burning both girls alive. The owner tries to get in, but the back door is locked, and he also locked the front. They're done for.
The next scene is at their funeral, where Ian begins questioning the preacher's comments and is led off by Lewis and Kevin. Afterward, Kevin finds Wendy kneeling at Jason's grave, and she begins to show him pictures of scenes that depict what's going to happen beforehand, including a picture showing a plane about to crash into the Twin Towers in New York. Suddenly, a strange wind blows over both of them, and Kevin tells Wendy he's going to get her some food.
The two go to a local drive-thru restaurant, unaware that Frankie is ahead of them in his little sports coupe. On the way, the two almost hit a truck in their vehicle, forcing the driver to jump aside. They get to the drive-thru of the restaurant, noticing a vehicle is pulling behind them and also to the side, blocking Wendy's exit. The sign also shows a bit of glitching out, and soon the radio kicks on, playing a creepy "Walking Behind You" song. Suddenly, Wendy and Kevin notice a runaway truck coming their way. They can't escape the vehicle, and they honk at Frankie to move aside, only to have him flip them off. The couple behind them move out, and they crack the windshield and jump out of the truck before the runaway truck hits it. The trucks collide, forcing Kevin's truck to spit its engine out of the front. It slides along the back of Frankie's car, and the fan cuts right into the back of his head, killing him. Wendy and Kevin go to check, and a "jolt" moment occurs when the fan sputters one last time, spreading Frankie's brains even further.
After a talk with the coroner, Kevin and Wendy begin to calculate death's design and who was sat where on the roller coaster. They look over the photos and decide to pay Lewis a visit while he's in the middle of a workout. Lewis thinks the whole thing is crap and proceeds to his workout, even as Wendy points out to Kevin that his photo shows a guy with swords, a weight dropping on his head, and a bear in the picture. (There's a tall bear statue and a sign with loose swords in the weight room). Lewis begins to work out with the other team members around him, causing the swords above his workout machine to rattle loose. Suddenly, some kind of accident jars a tooth out of the bear's mouth, forcing a weight lifter to drop his weights. Lewis stops for a moment, and the swords come down, missing him and instead slightly cutting into a cable on the machine he's working on. Lewis takes this moment of victory and lifts the weights one more time, only to have the cable snap and the two weights on top come down and smash his head to bits.
After a brief moment talking at the car, Wendy and Kevin make their way to the Home Depot-like shop where Ian and Erin work. Ian begins blasting away at birds with a nail gun, then sets it down. He then makes light of the stuff that's happening and tries to jokingly fool with Wendy and Kevin. However, soon some accidents are put in motion to put a forklift in motion to knock objects around, and it forces it to start lifting on a wall loaded with objects, including sharpened stakes and pieces of flat plywood. As Ian discusses the possibilities of death's designs, Wendy notices the stakes, and Kevin saves him as the items begin raining down. It soon starts stacking on top of each other, and one item penentrates a bag of sawdust, blinding Erin. She ends up falling backwards with her head against the nail gun, and about nine rounds end up getting fired through her head (and her hand), killing her. Ian is completely upset.
After a visit to the police station and the disbelief that follows, Wendy and Kevin split up, with Ian (not noticed) giving Wendy an evil stare. Wendy ends up falling asleep at her house, and Julie comes along to take back the bracelet, for good luck. Upon leaving, Wendy wakes up and realizes that she and her friend Perry were actually on the ride, upon the identification of the bracelet in a photograph. She calls up Kevin and informs him that his photo looks like something glaring, with bright light. It's then that Kevin informs her that he's overlooking security at a colonial fair, complete with fireworks, and Wendy starts heading out the door to the fair. Soon, the song she heard at the drive-thru kicks on again, and she notices a vehicle following her. She almost hits a wolf and continues to the fair.
Kevin notices Julie and her friends at the fair and tries to talk to her, but she runs off after being spooked out. Meanwhile, an actor leaves his cannon lighting stick on a cannon, knocking it sideways and forcing a cannonball to run along and knock one of the fireworks trailer cars off balance. Wendy shows up, wondering if Kevin will survive some kind of firework attack. Soon, the display is about to begin. As fireworks begin to go off, a couple of pranksters set off some of their own, startling a nearby horse. The horse begins running amuck, dragging a wooden stake behind him. Julie somehow ends up getting tied up in this, and almost gets impaled on some kind of rake machine that the horse jumps over. Kevin, however, is able to cut her loose. It's then that Wendy asks who was sitting next to her on the roller coaster, and she reveals it was Perry. As Perry realizes this and starts to stand up, the horse, still startled, pulls a flagpole off a trailer, which launches itself into Perry's chest, killing her.
After a close call with Kevin where he is nearly fried by a firework, Julie and Wendy begin to drag him off, only to run into Ian, who thinks that he is the cause for Wendy's death (indicated by a shirt she was wearing bearing his last name, the same name as the school). He confronts them, but then the firework cart settles over and aims the fireworks right at them. The others duck as the fireworks go off, which go all around Ian. He thinks he's safe and the others are next, but the fireworks ended up hitting a crane that loosens, carrying with it a sign that cuts Ian in half. He flips off the trio as he dies, and the screen fades to white.
Shift to five months later.
Wendy is now in another city, starting a new life with her new boyfriend and a roommate. She is riding in a subway train car with them, and starts to notice signs pointing to the deaths that previously occurred, as well as the "Walking Behind You" song being sung by a patron. She begins to motion to get off the car, but is stopped by Julie, paying a surprise visit and getting on the car. As she does, some guys in face paint drop an unfinished candy bar, which misses a trash can and goes onto the tracks, where a rat notices it. As the doors close, Wendy can't help but notice that the car number is "081", which, in the reflection of a mirror, are the numbers "180", the same as the flight from the first movie. She's nervous, but sits down to talk to Julie.
As they speak, she notices Kevin riding on the car, and goes over to ask why he's there. As he answers, she notices something is wrong as the lights begin to dim. The rat chews on the candy bar, but gets too close to some wires and fries himself, causing the tracks to switch over. The car goes haywire, and soon everyone is shifted as it flies off. Julie is cut to shreds by an oncoming train, and Kevin is pushed against a window and blasted apart as he scrapes in the tunnel. Wendy hangs on for dear life until the car crashes. Everyone is dead around her, and she crawls out, seeing her leg is severely injured. She then notices another train approaching, and not stopping. She screams for dear life.
We then flash back to on the train. It was another premonition she had while talking to Kevin - but this time, the premonition has taken place mere seconds before the accident which it depicted. Kevin grabs for the emergency brake and Julie attempts to help Wendy pry open the doors to the car, but the screen fades to black and the last thing we hear is the crashing of several subway cars.