The Book of Fate book by Brad Meltzer

"Six minutes from now, one of us would be dead. None of us knew it was coming."

So says Wes Holloway, a young presidential aide, about the day he put Ron Boyle, the chief executive's oldest friend, into the president's limousine. By the trip's end, a crazed assassin would permanently disfigure Wes and kill Boyle. Now, eight years later, Boyle has been spotted alive. Trying to figure out what really happened takes Wes back into disturbing secrets buried in Freemason history, a decade-old presidential crossword puzzle, and a two-hundred-year-old code invented by Thomas Jefferson that conceals secrets worth dying for.