Near Washington, D.C., there are two clandestine institutions: the world's most unusual laboratory and a secret CIA training camp. Drawn to these sites by a murder, ex-Secret Service agent Sean King encounters a dark world of mathematicians, codes, and spies. His search for answers soon leads him to more shocking violence-and an autistic girl with an extraordinary genius.

Now, only by working with his embattled partner, Michelle Maxwell, can he catch a killer...and solve a...