In the early years of the century, Nathan Walker leaves his native Georgia for New York City and the most dangerous job in America. A sandhog, he burrows beneath the East River, digging the tunnel that will carry trains from Brooklyn to Manhattan. Above ground, the sandhogs - black, white, Irish, Italian - keep their distance from each other until a spectacular accident welds a bond between Walker and his fellow diggers - a bond that will bless and curse the next three generations.

Years later, Treefrog, a homeless man driven below by a shameful secret, endures a punishing winter in his subway nest. In tones ranging from bleak to disturbingly funny, Treefrog recounts his strategies of survival - killing rats, scavenging for discarded soda cans, washing in the snow.

Between Nathan Walker and Treefrog stretch seventy years of ill-fated loves and unintended crimes. In a triumph of plotting, the two stories fuse to form a tale of family, race, and redemption that is as bold and fabulous as New York City itself.