Set in Kyoto in 2024, where drones map and preserve the city’s natural architecture and culture inside an infinite‑capacity quantum computer called Alltale, the story follows Naomi Katagaki, Takumi Kitamura, a hesitant high school student who loves reading. After a quiet post‑school day, a mysterious yatagarasu steals his library book, and a strange figure who only Naomi can see materializes: his future self, now grown, who goes by Sensei. The adult Naomi, Tori Matsuzaka (as Naomi Katagaki – future), explains that he has accessed Alltale from outside the real world to rewrite the past and rescue a classmate, Ruri Ichigyō, Minami Hamabe, who was struck by lightning at a fireworks festival and lies in a coma.
The teenage Naomi agrees to help, and Sensei grants him a unique power called God’s Hand—a translucent, gloved ability that can conjure almost anything so long as its construction isn’t overly complex. With guidance drawn from Sensei’s diary, Naomi begins to understand how to influence the data that binds their world, and a tentative romance develops between Naomi and Ruri as their feelings grow.
As the night of the festival arrives, Sensei’s interference triggers the Homeostatic System, and artificial beings in the form of kitsune men appear to correct the data. They are transported to the festival site, where Naomi wields God’s Hand to conjure a cataclysmic black hole, erasing not only the kitsune guardians but also the exact moment—an lightning strike—that would have hit the tree where Ruri waited. By removing that strike, Naomi saves Ruri and rewrites the past data to secure her life.
But the victory comes at a cost. Sensei pulls back the divine power and teleports Ruri away before vanishing, revealing that his plan was to restore Ruri’s original mental state inside Alltale so that the data could be synced with her real‑world coma and wake her up. Returning to the city, Naomi faces a new upheaval: thousands of kitsune flood Alltale, and the system begins to reboot, screening which data stays and which is erased, while red auroras spill across the sky. The world within Alltale shifts, and Naomi leaps into the red space, waking in a virtual realm where the yatagarasu promises to help him save Ruri and grants God’s Hand once more.
In the real world, Sensei clings to a waking Ruri as she emerges from her coma, but the kitsune menace soon circles the hospital room, signaling that Sensei’s world may also be nested inside Alltale. Teenage Naomi travels with Sensei to the staircase outside Alltale’s complex, aiming to return to their original reality. With Sensei’s aid, they outpace the kitsune, and Ruri returns to her own time through a portal. The kitsune converge into a terrifying behemoth that overwhelms Naomi, and Sensei sacrifices himself so that Naomi and Ruri can be together. Alltale’s management facility shuts down, its data collapsing into a new order that allows a parallel world to exist within Alltale. Naomi and Ruri share a kiss as the data is rewritten beyond recognition, and they greet a future in which a parallel world awaits.
The closing scenes jump to a final image: adult Naomi awakens on the Moon, where the yatagarasu’s voice lingers alongside an adult Ruri, suggesting Naomi’s earlier coma was a consequence of his own rescue mission and hinting that adult Ruri has transferred Naomi’s memories from Alltale to the real world, linking their fates across dimensions.
