Manga
Teiichi Niiya, a first-year middle school student at Seikyou Private Academy, encounters a ghost named Yuuko Kanoe after wandering into one of the school's abandoned buildings. Yuuko, who lacks memories of her past, explains that she is a spirit bound to the school. Intrigued, Teiichi resolves to uncover the truth behind her death by investigating the school's seven mysteries, which are intertwined with her existence. As they explore these ghost stories, they assist others affected by supernatural phenomena. Eventually, they learn that Yuuko's memories were sealed away in a darker manifestation of herself known as "Shadow Yuuko", and only by accepting this aspect can she recall her final wish—the reason she remains as a ghost.
After solving six of the seven mysteries, Yuuko's elderly sister reveals that the seventh mystery never existed. Yuuko then embraces her shadow self and recounts her tragic past. Sixty years prior, a plague struck the town, believed by the superstitious townspeople to be divine punishment for the Kanoe family's neglect of a sacred ritual. To appease the gods, the priest—Yuuko's father—was expected to sacrifice one of his daughters. Unwilling to choose, he planned to flee, but Yuuko's sister, swayed by the townspeople's hostility, conspired to lure Yuuko back to the school. Beneath the building lay a hidden shrine where the ritual was to take place. There, Yuuko was thrown into the shrine, her leg broken and the door nailed shut to prevent escape. Left to perish, she succumbed to starvation, dehydration, and her injuries. In her final moments, she cursed all those involved in her murder, wishing for their deaths. Shortly after, the perpetrators died from the plague or madness, though the epidemic persisted. Overcome with guilt, Yuuko's sister later opened the shrine door, only to be confronted by Yuuko's vengeful spirit. Unable to kill her, Yuuko instead severed her own hatred, sealing it away as Shadow Yuuko.
Having forgiven her sister and those responsible, Yuuko prepares to pass on, but at the last moment, she hesitates, realizing her desire to stay with Teiichi. Despite this, she vanishes, and the old school building—her former anchor—is demolished. As memories of her fade, Teiichi crafts new rumors, transforming the six mysteries into tales of Yuuko's past, her redemption, and her role as the school's guardian. Believing he has become her new regret, he spreads these stories to give her a renewed presence. Soon, a new rumor emerges—one of Yuuko finding love with a boy who vanishes with her. Teiichi rushes outside and reunites with Yuuko, embracing her as the legend concludes with ambiguity over whether she took him to the afterlife.
Later, Yuuko reappears at Teiichi's side, now bound to him rather than the school. In a final moment of intimacy, she leads him to a secluded part of the old building, dressed in a wedding gown. Confessing her wish to remain with him forever, she declares her love. Teiichi, grateful to have met her, reciprocates, and the two share a kiss. With a smile, Yuuko proclaims, "Let us go to Heaven together!"—marking the beginning of their eternal bond.
Anime
Teiichi Niiya, a first-year student at Seikyou Private Academy, befriends Yuuko Kanoe, a ghost with fragmented memories. Though he initially assists her without much focus on the school's supernatural legends, their dynamic shifts as he grows closer to his classmates Kirie and Okonogi. Unaware of her own emotional limitations, Yuuko suppresses her jealousy, unknowingly transferring those feelings—along with the lingering resentment from her past—into "Shadow Yuuko", a darker manifestation of herself.
As Teiichi helps Yuuko recover her memories, the truth of her death unfolds. A key figure from her past emerges: a melancholic girl named Asa-chan, whose family perished in the plague that ravaged their town. Initially distant, Asa feared infecting Yuuko but gradually warmed to her kindness. When the superstitious townspeople sought a sacrifice to appease the gods, they forced Asa into the role of Akahito-sama, a divine messenger tasked with selecting a victim. Yuuko, believing Asa was in danger, rushed to the shrine, only for the villagers to misinterpret Asa's fearful cry as a divine decree. In the ensuing chaos, Yuuko was thrown down the shrine's steps, sustaining fatal injuries. Contrary to initial assumptions, Yuuko's sister had no hand in her death—in fact, she had previously rejected Yuuko's self-sacrificial notions.
Teiichi uncovers this truth before Yuuko does, inadvertently causing her to lose awareness of him. To restore their connection, he confronts Shadow Yuuko, reconciling her with Yuuko's true self. He reveals that Asa survived and later became his grandmother, meaning Yuuko's sacrifice ultimately led to their meeting. With her regrets resolved, Yuuko begins fading from existence. In their final moments together, she shares a bittersweet day with Teiichi, culminating in a tearful kiss. Though Kirie lightly teases him afterward, she understands Yuuko's irreplaceable role in his heart.
Unknown to them, the kiss instills a new regret within Yuuko—her desire to remain with Teiichi. This emotion anchors her to him, ensuring she does not pass on. Instead, she becomes bound to Teiichi eternally, her existence now tied not to the school but to the boy who refused to let her go.
