A normal day on the subway is disrupted by the hijacking of a 6 train, designated Pelham One Two Three to indicate its point and time of origin. Four men armed with submachine guns detach the lead car and drive it into a tunnel with its 17 passengers as hostages. The hijackers are led by Ryder, a former mercenary, and consist of disgruntled former motorman Longman, violent ex-Mafia thug Joey Welcome, and powerful, laconic brute Steever. The gang threaten to execute one hostage per minute unless the city delivers to them a one million dollar ransom within one hour. One of the hostages is an armed undercover police officer, who considers the odds too overwhelming to attempt any confrontation and remains seated and quiet.