Published in Japan in 2023, Strange Buildings is a mystery horror novel by the pseudonymous author and YouTuber Uketsu. It’s the sequel to his best-selling novel Strange Houses, which was adapted into a major motion picture in Japan. The story follows a writer who, after the success of his previous book, receives submissions from readers about unsettling buildings with bizarre architectural features. He selects 11 unrelated cases to investigate with his friend Kurihara, an architectural draftsman, using floor plans, interviews, and archival documents to uncover a sinister conspiracy connecting them all. The novel’s unique, multi-modal format invites the reader to solve the puzzle alongside its characters, exploring how physical spaces can become instruments of harm and concealment through themes of The Moral Psychology of Architecture, Guilt as a Tool of Emotional Manipulation, and The Compounding Effect of Secrecy on Trauma.

Uketsu first gained popularity for his enigmatic online presence, where he presents mystery and horror stories while wearing a white mask to conceal his identity. Strange Buildings continues the innovative narrative style established in his debut, blending prose with visual evidence such as detailed floor plans, diagrams, and mocked-up articles. This structure positions the novel within the Japanese honkaku (“orthodox”) mystery tradition, which emphasizes logical deduction and provides the reader with all necessary clues to solve the central puzzle. Like its predecessor, Strange Buildings was a massive bestseller in Japan, solidifying Uketsu’s reputation as a prominent voice in contemporary popular fiction.

This guide refers to the 2026 HarperVia first edition of Jim Rion’s English translation.

Content Warning: The source material and guide feature depictions of death, death by suicide, child death, animal death, graphic violence, sexual violence, child sexual abuse, child abuse, emotional abuse, suicidal ideation, and ableism.

Plot Summary

An Author, famous for his book Strange Houses, receives numerous stories about unsettling buildings from his readers. Intrigued, he selects 11 unrelated cases to investigate, hoping that his friend Kurihara, the architectural draftsman he worked with on his last book, can help him find the connection between them. The investigation begins with Yayoi Negishi, who’s troubled by a dead-end hallway in her childhood home. Research reveals that a fatal accident involving the construction company Housemaker Misaki occurred in front of the house before it was finished, prompting the family to move the front door and create the strange hallway. The mystery deepens when an employee reveals that Yayoi’s mother later tried to have Yayoi’s bedroom completely removed from the house. This pattern of strange architecture and family secrets leads the Author to a company called Hikura Homes, Misaki’s main rival, which mass-produces poorly designed houses. A forensic cleaner tells the Author that Hikura houses can provoke people’s worst impulses, citing a familicide that occurred in one. Another case involves Shiori Hayasaka, who recounts how her childhood friend Mitsuko Hikura, who belongs to the same family that owns Hikura Homes, engineered the death of her own grandmother, a woman who always wore long gloves and skirts, by hiding her walking stick, causing her to fall down a dangerously designed staircase.

The Author’s research uncovers a web of historical events centered in the Chubu region of Japan. He finds an old journal from 1938 describing a strange watermill in the woods with a moving wall that conceals a hidden room. There, the owner of the journal, Uki Mizunashi, found what she described as a dead female egret with a missing wingtip. Decades later, a man named Kenji Hirauchi discovers that his new house was built over the foundations of this same watermill, preserving the hidden room where the body of a woman named Okinu, a maid from the nearby Azuma estate, was once sealed. Piecing together local history, the Author deduces that Okinu, pregnant from an affair, gave birth in the mill. Before dying, she hid her baby in an alcove, but the baby’s left arm was crushed by the moving wall. The baby was found and adopted by Uki’s uncle and aunt, who had the arm amputated to save her life. This child, Yaeko, grew up without her left arm.

The investigation pivots to a defunct cult from the 1990s, the Rebirth Congregation. The cult’s spiritual leader was the “Holy Mother,” a woman missing her left arm and right leg. The cult’s headquarters, the Hall of Rebirth, was a massive building shaped like her body. The cult, backed by Masahiko Hikura, the president of Hikura Homes, preyed on parents who felt guilty over “children born of sin” (306), referring to children from extramarital affairs. The cult’s central sacrament involved members sleeping in a room representing the Holy Mother’s womb to be “reborn.” They manipulated their members into giving the cult millions of yen by offering to remodel the members’ homes into miniature Halls of Rebirth, shaped like the Holy Mother. This is confirmed when the Author helps a designer, Ren Iruma, find a hidden room in his childhood home. The room is in the house’s “heart,” and inside is a doll of the Holy Mother; the house itself has been remodeled into her shape, revealing that Iruma’s parents were cult members. 

The Author then investigates a tragic house fire that killed the Matsue couple, neighbors of a woman named Chie Kasahara. Chie suspects that her father, a philanderer, murdered Mrs. Matsue, sneaking through their adjacent windows to kill her. The surviving Matsue son, Hiroki Matsu, suspects that his own devoutly Catholic father killed his mother. Both theories are fueled by the strange behavior of the fathers on the night of the fire. The Author discovers that Chie’s father later became “Uncle” to Naruki Mitsuhashi, a young boy who died from abuse, and was a member of the Rebirth Congregation, having remodeled his own house after Naruki was taken from him by his birth mother. After Naruki’s death, Chie’s father publicly accused the Holy Mother of failing to save the boy and then died by suicide. 

The Author presents his 11 files to Kurihara, who synthesizes the truth. The Holy Mother was Yaeko, the baby from the watermill. As an adult, she and her young daughter were forced into a brothel, where she lost her right leg while saving the life of Mitsuru Nishiharu, the child of another woman there. Yaeko’s life story became the doctrine for the Rebirth Congregation, founded by Masahiko Hikura, who had paid her debts and married her daughter. He used the cult to generate business for Hikura Homes. Chie’s father, Mr. Kasahara, joined the cult out of guilt from his affair with Mrs. Matsue, who had become pregnant and, feeling trapped, died by suicide. Her husband, Mr. Matsue, discovered her suicide note and, to hide the shame of the affair from his son, burned her body to destroy evidence of the pregnancy, accidentally dying in the fire himself. Yaeko’s later death after falling down the dangerous staircase was a murder orchestrated by the Hikura family after the cult was disbanded and no longer served a useful business purpose.

Finding a contradiction in the timeline, the Author confronts Mitsuru, who reveals the final, horrifying truth. The brothel was for pedophiles, and the children, including Mitsuru himself and Yaeko’s young daughter, were forced into sex work and abused by the brothel’s clients. Masahiko Hikura was a regular client of Yaeko’s daughter, whom he later married. This recasts the entire story: Yaeko’s daughter was the true mastermind behind the Rebirth Congregation. Filled with resentment for her mother, she forced her husband to create the cult as a grand, sadistic act of revenge, designed to publicly shame and psychologically torture her mother for having allowed her to be abused for years. Yaeko, consumed by her own guilt, endured the humiliation as penance.

Finally, the Author tracks down Mitsuko Hikura, who’s now a nurse for the elderly and is estranged from her family. She’s the daughter of Masahiko and Yaeko’s daughter, making Yaeko her grandmother. She confirms that her mother was a cruel tyrant who used everyone as puppets. Mitsuko confesses that her mother ordered her to hide Yaeko’s prosthetic leg to cause the “accident” that would kill her. However, Mitsuko initially believed that Yaeko overheard the plan and, knowing the punishment that Mitsuko would face for defiance, chose to fall down the stairs intentionally. This implies that her grandmother’s last act was a sacrifice to save Mitsuko from her own mother’s cruelty. However, when she discovered Yaeko’s prosthetic leg in a bookcase that only she had access to, Mitsuko convinced herself that she had killed Yaeko after all and had only dreamed that Yaeko sacrificed herself. Living with this knowledge, Mitsuko has abandoned her family’s wealth to spend her life atoning for the guilt she carries over her grandmother’s death.