Neverwhere

An ordinary city businessman stops to help an injured young woman on the street and finds that the act removes him from the life he understood. Work, home, money, and social recognition cease to function as expected. The search for an explanation leads beneath the city into a hidden society of abandoned stations, strange courts, dangerous markets, saints, monsters, and people who have slipped through the cracks above. The fantasy grows from familiar geography made literal and uncanny: names on a transit map become places, titles, and threats. Its central lead is decent rather than heroic, which keeps the wonder edged with inconvenience and fear. Readers get an urban descent story about kindness, invisibility, and the cost of finding a world that was always present but carefully ignored.