Another ordinary day in New York subway system is about to change completely when train Pelham 123 suddenly stops in one of the tunnels. There are no signs of problems on the line, but when dispatcher makes contact with the motorman it becomes obvious it is not gonna be an ordinary day any more.
During routing intra-yard movement of string of cars engineer makes a small mistake and his car, completely unmanned, not only moves into mainline, but also has set the throlle for 100%. Soon it turns out there are dangerous chemicals onboard.
