An organization known as GHQ, which is striving to avoid another epidemic under strict leadership, has been in charge of Japan, notably Tokyo, since the incident known as Lost Christmas in 2029, when the previously unidentified Apocalypse virus broke out.
Ten years later, the innocent youngster Shuu is caught in the crossfire between the GHQ and the Undertaker, a terrorist resistance organization that ostensibly seeks to obstruct government initiatives. During the process, he unintentionally acquires the Void Genome, which enables him to take weapons, tools, or other items, known as Voids, from other individuals. He is initially intimidated by the circumstances, but he quickly makes the decision to join the Undertakers, especially after he meets the female Inori, who plays a crucial role in the Undertakers.
