Neverwhere_

"Richard Mayhew is an ordinary young man with an ordinary life and a good heart. His world is changed forever when he stops to help a girl he finds bleeding on a London sidewalk. This small kindness propels him into a dark world he never dreamed existed. He must learn to survive in London Below, in a world of perpetual shadows and darkness, filled with monsters and saints, murderers and angels. He must survive if he is ever to return to the London that he knew."