Ten years ago this week John Kennedy was assassinated. His administration of the 'best and brightest,' his rich and glamorous family, were already the subject of admiring legend. And, as the President fell the legend took wing. Robert MacNeil was in the fatal presidential motorcade in Dallas. His report was among the first to reach the American people. Ten years later he returns to talk to Kennedy's family including Mrs Rose Kennedy and Senator Edward Kennedy, his most intimate advisers and his critics, to discover what remains - in Nixon's America - of the Kennedy Dream.