New York City, the near future: Mitchell Zukor works on the cutting edge of corporate irresponsibility, and business is booming. A brilliant mathematician, he spends his days calculating worst-case scenarios for FutureWorld, a consulting firm that indemnifies corporations against potential disasters. As Mitchell immerses himself in the calculus of catastrophe, he exchanges letters with Elsa Bruner--a college crush with her own apocalyptic secret--and becomes obsessed by a culture's fears. When Mitchell's darkest predictions come true and an actual worst-case scenario engulfs Manhattan, he realizes that he is uniquely prepared to profit. But what will it cost him?