Wataru Mitsuya, an 11-year-old boy, sees his life fracture when his father abandons the family for another woman. His mother’s ensuing mental collapse culminates in a gas-leak suicide attempt, propelling Wataru to seek fate’s alteration through Vision—a hidden realm accessed via an abandoned building’s portal, revealed by acquaintance Mitsuru Ashikawa.

Within Vision, Wataru pursues five gemstones to petition the Goddess of Destiny for his family’s salvation. His initial quest to mend his parents’ marriage collides with harsh trials: false murder accusations, navigating human-beastfolk racial tensions, and alliances with companions like Kee Keema, a waterkin, and Meena, a feline beastfolk. Struggling with repressed fury toward his absent father, Wataru violently projects his rage onto Vision’s symbolic manifestations of paternal figures before confronting the necessity to temper his inner darkness.

As Vision’s looming Blood Star catastrophe emerges—a celestial omen demanding sacrificial intervention—Wataru’s focus shifts from personal desire to ethical duty. Though Mitsuru exploits the realm’s power to resurrect his dead sister, Wataru forfeits his wish to instead plead with the Goddess for Vision’s deliverance from demonic annihilation.

Returning to reality with no memory of his odyssey, Wataru demonstrates hardened resolve: he prevents his mother’s suicide and crosses paths with Kaori Daimatsu, a formerly comatose girl now revived—subtle proof of Vision’s unseen influence on the tangible world.

Adaptations diverge in tone—the novel probes darker threads like peripheral characters’ trauma and Wataru’s subconscious vulnerabilities, while the film simplifies his trials into an adventurous framework. All versions trace his evolution from a child shattered by familial dissolution to an agent of selfless moral agency.