Two ex-Secret Service agents must face a dark world of violence, codes, and spies at a secret CIA training camp in this #1 New York Times bestseller about a mystery that could destroy the nation.

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 partner, Michelle Maxwell, who is battling her own personal demons, can he catch a killer...and stop a national threat.