ABOVE THE BLUE SEA, birds flew in flock. An abnormally tall man with a black hooded trench coat walked out of a fog of shadows, staring up at the cloudy sky. Looking around at what used to be a city called Miami in South Florida, he surveyed the marshes that conquered the area. The drowned city of ghosts had only a few thousand residents who were too stubborn to move. He turned and saw an elderly man fishing off the coast. The frail fisherman noticed the man staring at him i