In 2039, Shu Ouma is a socially awkward student living in Japan, where it is under the strict rule of the government organization named GHQ following the outbreak of the Apocalypse Virus ten years earlier. While going to his warehouse studio, he encounters Inori Yuzuriha, an internet singer of the band Egoist, who is recovering from her wounds after stealing the Void Genome, a genetic weapon stored in a vial, from GHQ, keeping it safe inside her pet robot Funell. Inori is then captured by the GHQ Anti-Bodies division led by Major Guin. To make amends upon her request, Shu brings the Void Genome to Inori's boss, Gai Tsutsugami, leader of the resistance group called Funeral Parlor (Undertakers). However, Guin orders the Anti-Bodies to exterminate the residents of Roppongi in order to find the Void Genome. As Funeral Parlor and GHQ battle, Shu goes to rescue Inori, protecting her when a GHQ humanoid war machine known as an Endlave tries to attack them. The attack shatters the vial holding the Void Genome, giving Shu the "Power of the King", which he uses to extract Inori's Void, in the form of a sword, in order to destroy the Endlave.