A massive FBI manhunt for an elusive and appallingly adept serial bomber is underway. He's just hit his sixth target, the Boon Dam at Idaho, killing a dozen innocent people. But the bomber, who has been dubbed "Green Man" by the press, insists on these drastic acts of violence—each one carefully selected to destroy an environment-threatening target—is necessary to draw the world's attention to the climate change emergency. The FBI does not have any actual leads. It's as if Green Man can predict every step of their investigation, skillfully evading all of their standard tactics. Until young agent Tom Smith approaches the leader of the task force with unforeseen insight. Tom, a training computer programmer, might be the only person with the unique skill set required to catch Green Man before he strikes again..