Beneath the streets of Manhattan, on an afternoon like any other, four armed men hijack a subway carriage, demanding a $1 million ransom within an hour – or they’ll start executing their hostages. Upstairs, in the New York Transit Authority’s control room, world-weary transit cop Lt Garber (Walter Matthau) is forced into a deadly game of cat and mouse with the cool, calculating “Mr Blue” (Robert Shaw), parrying the demands of both the hijackers and the city’s authorities as the clock counts down to the fateful deadline.