Through her research on twins and the genetic components of aggression, scientist Jeannie Ferrami makes a startling discovery. Using a restricted FBI database, she finds two young men who appear to be identical twins: Steve, a law student, and Dennis: a convicted murderer. Yet they were born on different days, to different mothers, in hospitals hundreds of miles apart. As Ferrami delves into their backgrounds, she unwittingly locks horns with some of the most powerful forces in America, including the university where she works, The New York Times, even the Pentagon. What secret has Ferrami uncovered? Can she trust her boss and mentor, or must she