Once a year, the most powerful people in the land gather together in one room. The Queen, the Prime Minister and Cabinet, the judges and the bishops - leaders spiritual and temporal - assemble in the House of Lords for the State Opening of Parliament. On this particular Lords' Day, the gathering is still more impressive, for sitting beside his mother is the heir to the throne, and up in the galleries are the sons of both the US President and the British Prime Minister. But all are about to be taken hostage. It is the greatest siege of all time. It will lead some to selfless sacrifice, others to lose the respect of those they love most dearly . . .