Neverwhere

Richard Mayhew is a young businessman with a good heart and a dull job. When he stops one day to help a girl he finds bleeding on a London sidewalk, his life is forever altered, for he finds himself propelled into an alternate reality that exists in a subterranean labyrinth of sewer canals and abandoned subway stations below the city. He has fallen through the cracks of reality and has landed somewhere different, somewhere that is Neverwhere.