Dusk Maiden of Amnesia

The anime series has been licensed by Sentai Filmworks in North America.

The story takes place at Seikyou Private Academy: an extremely old school with several buildings, each built at different points in history without care for the existing architecture. Many of them overlap and mix with each other, resulting in an unintentional maze-like structure, within which the untrained can easily lose their way. The School was built over an old shrine, which is where Yuuko died. Since her body and regrets are tied to the school, she is unable to leave the school grounds even if she wanted to. In the series, a 'Ghost' is formed from the person's regrets while they were alive. One can see them only if believing in the ghost's existence—but depending on one's expectations and knowledge, what they see will vary greatly: from Yuuko's true form (as she sees herself and was before she died) to a demonic entity.

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.

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.

Teiichi Niiya (新谷 貞一, Niiya Teiichi) Voiced by: Tsubasa Yonaga (Japanese); Clint Bickham (English) Teiichi joins the Paranormal Investigations club made by Yuuko in order to find more information about Yuuko's death. He gets easily flustered when Yuuko teases him. As he interacts with Yuuko, the two of them eventually fall in love with each other. Yuuko Kanoe (庚 夕子, Kanoe Yūko) Voiced by: Yumi Hara (Japanese); Emily Neves (English) Mainly known as "Yuuko-san" from the ghost stories in the school, she is the infamous ghost of Seikyou Academy and the President of the Paranormal Investigations club. She is cheerful and enjoys tricking people, but gets very jealous and angry when a girl tries to get close to Teiichi to the point of almost causing injury at times. She is flirtatious towards Teiichi, often teasing him and does not mind having her "body" being seen by him, except her skeleton (since it is the peak of her nakedness). The various ghost stories of the school are all related to Yuuko in some way. She is in love with Teiichi. Momoe Okonogi (小此木 ももえ, Okonogi Momoe) Voiced by: Misato Fukuen (Japanese); Brittney Karbowski (English) A member of the Paranormal Investigations Club. She is indebted to Teiichi for saving her from the Underground demon legend (which was fabricated by Yuuko) and looks for many ghost stories in the school to help the club. She is the only member of the club that cannot see Yuuko despite learning of her existences but despite it all, she believes that the other two can see Yuuko. She in fact, saw Yuuko before but she saw only the Underground demon legend since Yuuko can be seen by anyone aware of her but their perception changes with their awareness. Okonogi had heard of the legend and then became aware hence she saw her on that form. When Teiichi "killed" the demon she could not see Yuuko in any form. She admires Teiichi and likes him. Kirie Kanoe (庚 霧江, Kanoe Kirie) Voiced by: Eri Kitamura (Japanese); Jessica Boone (English) A member of Paranormal Investigations club and Yuuko's grandniece. She is the only character other than Teiichi and her own grandmother to be able to see Yuuko. She originally believed that Yuuko was an evil spirit until she learns the truth: that she was seeing Shadow Yuuko. Kirie resembles Yuuko albeit with short hair and a smaller bust as her grandmother is Yuuko's younger sister. She has some feelings for Teiichi, however she cannot confess them but tries to in ways such as suggesting that if need be she could replace Yuuko for Teiichi if she grew out her hair. She is easily frightened especially of ghosts except for Yuuko.

Written and illustrated by the manga artist duo Maybe, they first published two one-shots in Square Enix's Gangan Powered on April 22 and October 22, 2008. Dusk Maiden of Amnesia was later serialized in Square Enix's Monthly Gangan Joker from April 22, 2009, to June 22, 2013. Ten compiled tankōbon were released between August 22, 2009, and November 22, 2013. Additionally, an official guidebook and an anthology by several authors were published on November 22, 2012. Square Enix started publishing the manga digitally in English on its Manga Up! Global service on August 4, 2024.

A drama CD of the manga was published by Frontier Works and released on July 22, 2010.

An anime adaptation by Silver Link was announced in the January issue of Square Enix's Monthly Gangan Joker and aired in Japan between April and June 2012 with 12 episodes with a 13th episode included in the 6th DVD and Blu-ray Disk volumes. It was also simulcasted by Crunchyroll. The opening theme is "Choir Jail" by Konomi Suzuki whilst the ending theme is "Karandorie" (カランドリエ) by Aki Okui with a special version sung by Yumi Hara in episode 11. In episode 12 the insert song is "Requiem" by Nao Hiiragi. The anime has been licensed by Sentai Filmworks in North America and released a dubbed version of the anime on DVD and Blu-ray Disc on June 4, 2013. MVM Films have licensed the anime for the United Kingdom for release on DVD on February 10, 2014.