Introduction to 2039 Japan
Following a biological disaster in 2029 known as the "Lost Christmas," Japan has lost all its political independence. The nation is under the strict, martial law of a quasi-governmental military force called GHQ, which brutally suppresses the population. A rebel faction named Funeral Parlor, led by the charismatic Gai Tsutsugami, fights a daily guerrilla war to liberate the country.
Shu Ouma and the Void
The story begins when Shu Ouma, an ordinary high school boy, crosses paths with Inori Yuzuriha, a famous internet idol and secret rebel. During an attack by GHQ mechs, Shu accidentally shatters a stolen vial containing the genetic weapon known as the "Void Genome". This grants him the "Power of the King," a supernatural ability allowing him to extract "Voids"—physical weapons formed from a person's soul—directly from the bodies of others.
Joining Funeral Parlor
Armed with this new power, Shu is reluctantly drafted into Funeral Parlor to assist their combat operations against GHQ. He uses his classmates' and fellow rebels' Voids to destroy enemy mechs, slowly overcoming his naturally cowardly personality. However, Shu constantly struggles with the heavy burden of leadership and the moral implications of using human souls as disposable weapons.
Origin of the Virus
As the conflict escalates, the dark history of the Apocalypse Virus is revealed to be intimately tied to Shu's forgotten childhood. His older sister, Mana, was the original "Eve" of the virus and caused the catastrophic Lost Christmas outbreak when a young Shu rejected her insane romantic advances. Gai is also revealed to be Shu's childhood friend, "Triton," who survived the disaster and dedicated his life to saving Mana from the virus's control.
First Climax and Tragedy
GHQ, secretly controlled by the ancient cult Da'ath, attempts to trigger a second global outbreak by resurrecting Mana using Inori's body as a vessel. To stop the apocalyptic ritual, Gai sacrifices himself by allowing Shu to stab a sword directly through his chest to destroy Mana's containment pod. Gai's death temporarily halts the apocalypse, but the battle leaves Funeral Parlor completely shattered and its members scattered.
Tennouzu High School Quarantine
In the chaotic aftermath, GHQ establishes a massive quarantine zone called "Loop 7," trapping Shu and his classmates inside Tennouzu High School. With supplies rapidly dwindling and GHQ threatening to execute the students, Shu is forced to become the student council president to maintain order. He attempts to rule fairly, but the extreme stress and constant threat of starvation push the student body to the breaking point.
Shu's Descent into Tyranny
Tragedy strikes when Shu's closest friend, Hare, is brutally killed while trying to protect him during a dangerous supply run. Overcome with grief and trauma, Shu abandons his kindness and establishes a ruthless caste system based on the power rankings of the students' Voids. He becomes a hardened tyrant, forcing weaker students into dangerous labor while violently suppressing any dissent to ensure the school's survival.
The Return of Gai
Shu successfully leads a breakout from the quarantine zone, but his abused classmates immediately mutiny against his dictatorship. In a shocking twist, a resurrected Gai appears, having been brought back from the dead by the Da'ath cult as a cold, villainous agent. Gai brutally severs Shu's right arm, stealing the "Power of the King" for himself and kidnapping Inori.
Shu Seeks Redemption
Left crippled and powerless, Shu hits rock bottom until his stepmother, Haruka, betrays GHQ and steals a third Void Genome. Realizing the weight of his past mistakes, Shu injects himself with the serum, regaining his powers in his left arm and assuming command of the remaining Funeral Parlor forces. He resolves to save Inori and defeat Gai, no longer acting as an angry tyrant but as a savior willing to bear everyone's sins.
The Final Confrontation
Gai plans to broadcast the Apocalypse Virus globally from Tokyo Tower to force human evolution and allow Mana to fulfill her cursed destiny. Shu launches a massive final offensive alongside his remaining allies, battling his way to the top of the tower where he defeats Gai in a final duel. Dying peacefully, Gai reveals he intentionally played the villain so Mana could complete her role as Eve and finally rest in peace.
Inori's Ultimate Sacrifice
Despite winning the battle, Shu discovers Inori has been completely consumed by the crystallized virus and is on the verge of death. He uses his power to absorb all the virus and Voids in the world into his own body, intending to sacrifice himself to save humanity. However, in a metaphysical realm, Inori sacrifices her own soul and body, taking Shu's place in death so he can survive.
Epilogue and World Aftermath
With the virus permanently eradicated by Inori's sacrifice, the GHQ tower collapses and the survivors escape. Years later, a rebuilt Tokyo is shown where a now-blind Shu with a prosthetic arm gathers with his surviving friends to celebrate a birthday. In the final moments, Shu is seen peacefully listening to Inori's music, proving her memory and spirit live on within him.