Two years after hacker Fujimaru Takagi, known online as Falcon, stopped the first Bloody Monday terrorist plot, a new conspiracy takes aim at Japan while Falcon himself has vanished from view. Fujimaru, trying to live an ordinary life studying for college entrance exams, gets pulled back in when his investigation uncovers a lethal virus and a device the terrorists call 'Pandora's Box', the launch trigger for America's nuclear arsenal. Tracking the people who want it forces Fujimaru back into the world he thought he'd left behind.