Threshold — Ben Mezrich

For a lifetime, he has channeled the fear and guilt of a childhood trauma into an impassioned mission to save others. Now, inside seventy-two hours, Jeremy Ross will have to defuse an audacious plot to genetically rewire the human race. And in a heartbeat, allied with an ex-lover on a desperate quest of her own, he'll experience the greatest terror man or woman ever faced - while confronting a threat more devastating than any living creature can ever imagine.