Fifteen-year-old Nik Granjer hates the Bug. It was the Bug that destroyed the world when it wiped out over ninety percent of humanity a hundred years ago. Even now, the Bug kills anyone whose heart rate goes over 140 beats per minute. That's why the Prime Administrator gave everyone the papas - digital wrist monitors that put people to sleep when their heart rate gets too high. The Papas saved humankind. But one night on the border of New Frisko, when Nik tampers with his Papa and discovers there is more to the Bug than he thought, a brutal enforcement squad from the city suddenly forces Nik into hiding. On the run and searching for allies, Nik's only hope is to escape with his life and discover the truth about the Prime Administrator's regime and the origins of the Bug. But can Nik and his friends keep their heart rates under 140 when it matters most?