After the Wall Street crash of 2008, the richest man in town is the mayor. Billionaires shed apartments like last season’s fashions, even as the country’s economy turns inside out. The young and careless go on as they always have, getting laid and getting laid off, falling in and out of love, and trying to navigate the strange world they traffic in: the Internet, complex financial markets, credit cards, pop stars, micro-plane cheese graters, and sex apps.