It is pouring with rain at one minute to midnight on Friday the thirteenth, and the driver of a London bus is peering through his blurred windscreen as his vehicle sails down an empty road. Suddenly, lightning strikes, and a vast crane above topples into the path of the oncoming bus... Then Big Ben begins to wind backwards. Time recedes. And we discover the lives of all the passengers and the events that brought them to that late-night bus journey, from the con-man with a hundred-pound cheque to the businessman's distraught and elderly wife. Time flows on, inevitably, to the crash -- and past it, as some live and some die.