On December 24, 2029—a day colloquially referred to as the "Lost Christmas"—the Apocalypse Virus swept across Japan, killing its citizens and throwing the nation into total chaos. To restore order, the United Nations dispatched the GHQ to help manage the crisis by containing the outbreak, a move that simultaneously stripped the country of all political autonomy. Ten years later, Japan remains under their control, unable to escape their harsh rule. Discontent with the nation's condition, a resistance faction called the Funeral Parlor seeks to free Japan from the GHQ. Under the leadership of the charismatic Gai Tsutsugami, the group plans to steal a vial holding the "Void Genome" to advance their objectives. The vial comes into the possession of internet vocalist Inori Yuzuriha, who subsequently becomes the target of the GHQ's Anti-Bodies forces. With no other options, she takes shelter in a warehouse, where she encounters Shuu Ouma—a socially awkward high school student and devoted fan of her music. Shuu is pulled into the conflict immediately after rescuing Inori, and the Void Genome breaks in his hand, bestowing upon him the "Power of the Kings." As he learns to master his powerful new ability, Shuu must now battle to liberate Japan from its cruel oppressors.