Captain Brian Engle, a 43-year-old American Pride pilot, has just completed a harrowing flight from Tokyo to Los Angeles when he learns that his ex-wife, Anne, has died in an apartment fire in Boston. Exhausted and grieving, he boards American Pride Flight 29, the red-eye from Los Angeles to Boston, as a deadheading passenger, a pilot riding along without flying duties. The 767 carries roughly 150 passengers and a full crew. Brian falls asleep shortly after takeoff.
Approximately three hours into the flight, 10-year-old Dinah Bellman, a blind girl traveling with her Aunt Vicky, wakes to find her aunt's seat empty. Using her acute senses, Dinah determines that the surrounding seats are vacant, though personal belongings remain behind. Brian wakes and discovers that only about 10 passengers remain on the entire aircraft, all of whom had been asleep. The flight crew has vanished along with everyone else. Among the survivors are Albert Kaussner, a 17-year-old violinist; Nick Hopewell, a composed Englishman; Bob Jenkins, an elderly mystery novelist; Laurel Stevenson, a young woman who takes charge of Dinah; Don Gaffney, an older man; Craig Toomy, an agitated businessman; and Bethany Simms, a teenager. Searching the cabin, they find dental fillings, surgical pins, and a pacemaker among the items left behind, suggesting the vanished were removed from their very bodies.
Brian and Nick break down the locked cockpit door and find the plane flying on autopilot. Brian takes the controls and tries every radio frequency but receives no response. Where Denver's lights should be visible, they see only darkness. Bob deduces that whatever happened selectively removed those who were awake, sparing only the sleeping.
Brian diverts the flight to Bangor, Maine, chosen for its long runway and overland approach. Craig loudly insists they continue to Boston for a critical business meeting, and Nick silences him with a painful grip on his nose. Craig's fixation stems from deep psychological damage. His father terrorized him as a child with stories of creatures called "the langoliers," monsters made of hair, teeth, and fast little legs that devoured lazy children. Craig became a driven overachiever, but he recently made a reckless purchase of worthless Argentinian bonds at the Desert Sun Banking Corporation, fabricating data to push the deal through. Facing ruin, he views the diversion as a conspiracy and resolves to kill anyone in his way.
Brian lands at Bangor International Airport with no radio guidance and no runway lights. The airport is utterly deserted. Inside the terminal, phones are dead, the power is out, and the air carries no smell or taste. Sounds fall flat without resonance. Craig slips away and finds a loaded revolver in the Airport Security office. Dinah stands at the terminal windows and announces she hears a faint sound from the east, something like cereal crackling in milk. She warns them that something is coming.
Bob Jenkins conducts experiments that reveal their predicament. Matches from the terminal will not light, but Bethany's matches from the plane strike immediately. Food from the terminal is tasteless, and beer is flat. Bob presents his theory: They have not traveled to another dimension but backward in time, through what he calls a "time-rip," a hole in the temporal fabric. The world they occupy is the recent past, an empty, discarded version of reality. The plane carried its own present with it, preserving the vitality of objects aboard.
Craig emerges from hiding and seizes Bethany at gunpoint, demanding they fly him to Boston. Albert charges him with his violin case. The gun fires with only a feeble pop, and the bullet bounces off Albert's chest, its propellant as depleted as everything else in this dead world. Albert knocks Craig unconscious, and Nick ties him up.
Albert then makes a crucial discovery. He notices the 767 looks brighter and more solid than its surroundings, leading him to hypothesize that objects from this world might regain their vitality aboard the plane. They test this by carrying airport matches, flat beer, and a tasteless sandwich onto the 767. After a brief delay, the matches light, the beer fizzes, and the sandwich tastes wonderful. This means jet fuel from a parked Delta 727 might burn once pumped into the 767's tanks.
While the others are occupied, Craig works free, finds a butcher knife, and hides behind the restaurant counter. Dinah senses his presence and walks toward him, reaching out to comfort him. Craig, lost in delusion, sees her as the "head langolier" and drives the knife into her chest. He flees and kills Don Gaffney with a letter-opener before Albert beats him unconscious. Nick pulls the knife from Dinah's chest and applies emergency bandaging but knows her wound is grave. He spares Craig at Dinah's insistence that they will need him.
Brian pumps fuel from the Delta jet while the sound from the east grows into a deafening roar. Trees fall and buildings collapse as something devours everything in its path. Dinah, fading, uses a psychic ability to project a vision into Craig's mind: a glowing angel and a boardroom full of bankers. Guided by this hallucination, Craig stumbles onto the tarmac.
The langoliers arrive: ball-shaped creatures whose rippling surfaces conceal monstrous faces and semicircular mouths full of gnashing teeth. They leave trails of absolute nothingness, voids where reality itself has been erased. The lead creatures pursue Craig and consume him. Brian guns the engines, races down the disintegrating runway, and lifts off. Bob explains that the langoliers are "the time-keepers of eternity, always running along behind, cleaning up the mess . . . by eating it."
They fly west toward the time-rip. Dinah dies quietly, her head in Laurel's lap. Before dying, she tells Laurel that she saw through Craig's eyes and that "everything was beautiful . . . even the things that were dead." Nick confides to Brian that he is a British covert operative sent to Boston to assassinate the mistress of a politician who funds the Irish Republican Army (IRA), and that he had decided to quit.
They spot the time-rip, a lozenge-shaped opening cycling with aurora-like colors. Bob realizes the critical problem: When they originally passed through the rip, everyone awake vanished. If they fly through conscious, they will cease to exist. Brian can depressurize the cabin to knock everyone unconscious, but someone must stay awake to restore pressure afterward, or they will all die. That person will vanish. Nick volunteers. He asks Laurel to tell his estranged father that Nick had decided to quit, and to remind the old man of "the daisies" and "the day behind the church in Belfast."
Brian depressurizes the cabin. The passengers lose consciousness one by one. Nick, wearing an oxygen mask, watches the rip fill the cockpit with cascading color. As Flight 29 plunges through, he twists the pressure back to full and ceases to exist. Only his dental fillings and a Teflon disc from a knee replacement fall to the cockpit floor.
Brian wakes over Los Angeles to find the city dark and apparently empty. Laurel despairs, believing Nick died for nothing. But Albert insists something is different: There is a breeze, sounds have regained their resonance, and the air carries smells. Brian crash-lands the fuel-depleted 767 at LAX. They hear a growing, sourceless choral hum, and Bob explains that this westbound passage has delivered them into the future, a world on the verge of being born. They huddle against a wall as the present catches up: Fluorescent lights race on in expanding circles, and ghostly figures materialize into real people filling the terminal. A little girl sees them appear and exclaims about the new people. Overhead speakers announce that eastbound flights are delayed due to unusual weather over the Mojave Desert. The survivors, laughing and weeping, walk together out of the terminal and into the living world.