A man calling himself Ryder and his accomplices – Bashkin, Emri, and former train operator Phil Ramos – hijack Pelham 123, a New York City Subway 6 train, at 77th Street. Uncoupling the front car of the train below 51st Street, they take the passengers hostage. Metropolitan Transportation Authority employee Walter Garber, working the Rail Control Center as a train dispatcher, receives a call from Ryder, demanding $10 million in cash to be paid within 60 minutes. Ryder warns that every minute he waits past the deadline, he will kill a hostage.
Bashkin kills a suspicious New York City Transit Police officer, and all the passengers not in the front car, except the motorman, are released. Garber reluctantly negotiates with Ryder as Ramos and Emri set up Internet access in the tunnel. On his laptop, Ryder watches the Dow Jones Industrial Average plunge nearly 1,000 points in response to the hijacking. A hostage's laptop also connects to the Internet, and its webcam allows the control center to observe Ryder and Ramos. Lieutenant Camonetti of the New York City Police Department Emergency Service Unit takes over negotiations, which infuriates Ryder, who kills the train's motorman to force Camonetti to bring Garber back.
Camonetti learns that Garber is being investigated for allegedly accepting a $35,000 bribe over a contract for new Japanese subway cars. Ryder also discovers the allegations online and forces Garber to confess by threatening to kill a passenger. To save the hostage, Garber claims that he was offered the bribe while deciding between two companies, using the money to pay for his child's college tuition, and insists he would have made the same decision regardless. The mayor agrees to Ryder’s ransom, ordering the police to deliver it. En route, the police car is involved in an accident and fails to deliver the money in time. Garber attempts to bluff Ryder that the ransom has arrived, unaware he has been monitoring events on his laptop. Ryder threatens to execute a child's mother, but another hostage, a former soldier, sacrifices himself and is killed. A brief gunfight erupts after an Emergency Services Unit sniper is bitten by a rat and discharges his weapon, killing Ramos.
Based on clues from Garber’s conversations, the police discover that Ryder is Dennis Ford, a manager at a private equity firm who was sentenced to prison for investment fraud. Ford had agreed to a plea bargain to serve three years, but received ten years instead. One of the mayor's aides mentions the extreme drop in the major stock indexes, and the mayor deduces that Ryder is attempting to manipulate the market via put options. Ryder demands that Garber deliver the ransom himself, and Garber is given a pistol and flown to the terminal. Ryder brings Garber aboard and orders him to operate the train down the tunnel below 33rd Street, where Garber and the hijackers exit, rigging the train to go on without them. Garber manages to separate himself at a railway crossing and follows Ryder to the Waldorf Astoria hotel. Ryder parts from Bashkin and Emri, who are shot dead after being surrounded by police and provoking deadly force in an apparent suicide-by-cop. The train comes to a halt safely just before Coney Island, and the police discover Ryder is no longer on board.
Ryder hails a taxi, followed by Garber, and finds that his scheme has amassed $307 million. He reaches the Manhattan Bridge's pedestrian walkway, where Garber holds him at gunpoint. Ryder gives him a 10-second ultimatum to pull the trigger, and in the final seconds, pulls out his own gun and forces Garber to shoot him. Telling Garber, "You're my goddamn hero", Ryder collapses and dies (as Garber solemnly looks on while Camonetti observes approvingly from a chopper).
The mayor thanks Garber and assures him the city will "go to bat" for him over his bribery admission. The film concludes as Garber returns home to his wife with groceries he had promised to pick up.
Denzel Washington as Walter Garber, an MTA subway dispatcher, who is negotiating with the hijackers.
John Travolta as Dennis 'Ryder' Ford / Mr. Blue, the leader of the hijackers.
John Turturro as Lieutenant Vincent Camonetti, hostage negotiator with the NYPD's Emergency Service Unit.
James Gandolfini as the Mayor of New York,
Luis Guzmán as Phil Ramos / Mr. Green, former MTA motorman, one of the hijackers.
Michael Rispoli as John Johnson,
Gbenga Akinnagbe as Wallace, one of the hostages on the train.
Frank Wood as Police Commissioner Sterman
John Benjamin Hickey as Deputy Mayor LaSalle
Gary Basaraba as Jerry Pollard,
Ramón Rodríguez as Delgado, an MTA train dispatcher
Robert Vataj as Emri / Mr. Brown,
Jake Siciliano as An Eight-Year-Old Boy, hostage with his Mom
Aunjanue Ellis as Theresa, Garber's wife
Tonye Patano as Regina, MTA conductor on the hijacked train
Jason Butler Harner as Mr. Thomas, a hostage who has to pee
Victor Gojcaj as Bashkin / Mr. Gray, the most aggressive of the hijackers.
Brian Haley as Police Captain Hill
a film adaptation of the novel of the same name by Morton Freedgood (writing under the pseudonym John Godey), and is a remake of the original 1974 film adaptation of the same name, which was also remade in 1998 as a TV film.