Gregg Hurwitz Out of the Dark

Someone, at the very highest level of government, has been trying to clean up the Orphan program but killing all the remaining orphans and their trainers. After Evan's mentor and the only father he ever knew was killed, he decided to strike back. His target is the man who started the Orphan program and who is now the most heavily guarded person in the world: the President of the United States. But President Bennett knows that Orphan X is after him and, using weapons of his own, he's decided to counter-attack. Bennett activates the one man who has the skills and experience to track down and take out Orphan X--the first recruit of the program, Orphan A. Now it's Orphan vs. Orphan with the future of the country--even the world--on the line.