As a sequel, Uketsu’s novel carries on its predecessor’s method of looking through floor plans for unusual design elements, which the Prologue of the novel references. The first chapter, or “file,” thus teaches the reader to navigate the format of the novel, establishing the floor plans as a recurring motif and as primary evidence that demands logical interpretation. This technique firmly roots the narrative in the Japanese honkaku, or “orthodox,” mystery tradition, which invites the reader to solve a crime alongside the protagonist using a shared set of clues. The plans function as visual arguments, presenting problems that characters and readers must deconstruct through deduction while also hinting at the novel’s larger thematic ideas. For instance, Yayoi Negishi’s hand-drawn floor plan places the titular “hallway to nowhere” of the first file in between the parents’ room and Yayoi’s room (18). While the vestigial hallway hints at the fraught history of Yunosuke Kasuga’s tragic death, it also physicalizes the gap between child and parent, visually representing the distance between the parents’ secret lives and what the child perceives of them. This is echoed in the second file, where it’s concluded that the teen who killed his family resided in the storage closet because it was the only part of the home where he could get any privacy. On the other hand, the lack of privacy for everyone else, including the teen’s mother, who is deduced to have killed the grandmother because she felt she was constantly being judged as an inadequate homemaker, drives the psychological circumstances of guilt that serve as a recurring undercurrent throughout the entire novel.

The narrative structure, which frames each case as a “file” collected by the Author, creates a fragmented, documentary-style presentation that gradually builds a larger meta-puzzle. Though the Prologue frames Kurihara as the person who will eventually piece the files together, the disparate quality of the files feeds into the idea that the reader is being invited to solve the puzzle as well. In this way, the Author’s role evolves from that of a passive interviewer, whose initial goal is to bring his subject “some peace,” to a proxy for the reader, who uncovers newspaper archives and reinterprets crime scenes for Kurihara to synthesize. This shift is important when he challenges the official police narrative in the Tsuhara case, proposing a new sequence of events based on the victims’ injuries and positions. By pointing out the inconsistency between the official records and the evidence, the Author is encouraging the reader to do the same. The collage of interviews, archival research, and found documents forces the reader to synthesize information across different time periods and narrative modes. The abrupt transition in File 3 to an excerpt from a 1938 book, Records of Beautiful Sojourns, informs this disruption by introducing a historical layer from a completely different source than the first two files. The structure suggests that the true mystery is encoded in the connections between each file, a sprawling puzzle that can only be solved by assembling disparate pieces of evidence.

The forensic cleaner Tatsuyuki Iimura’s assessment of the Tsuhara house provides a clear articulation of The Moral Psychology of Architecture as a theme. He argues that the home’s flawed design, a product of the cost-cutting, mass-production model of Hikura Homes, fostered the conditions for the family’s self-implosion. The lack of hallways destroyed privacy, the clustering of doorways created constant congestion, and the adjacency of the kitchen to the bedridden grandmother’s room bred resentment. Iimura concludes that while the house wouldn’t cause problems over a short stay, years of accumulated stress could make someone “crazy,” suggesting that the building itself “nurtured the darkness” in its inhabitants (59). This form of architectural influence is thus insidious; through inattention to the psychological impact of the cost-cutting design, the house eroded its inhabitants’ mental and emotional well-being. The house actively cultivated tragedy, demonstrating how poorly considered living spaces, driven by corporate greed, can systematically degrade mental health and family relationships.

Beyond the physical layout of the homes, the mysteries are deeply rooted in unspoken family histories, showing The Compounding Effect of Secrecy on Trauma. Yayoi’s investigation is driven less by architectural curiosity and more by a deep need to understand her mother’s contradictory behavior. She admits that her “lost twin” theory was “born out of hope” (34), a desperate attempt to find a justifiable reason for a lifetime of maternal harshness. Mrs. Negishi’s refusal to speak about the fatal accident on the property, and her later secret attempt to demolish Yayoi’s bedroom, represent an extreme level of avoidance. By walling off the past both physically and emotionally, she trapped her daughter in a state of confusion that has persisted long after her death. The “hallway to nowhere” thus becomes a metaphor for Yayoi’s emotional inheritance: a dead-end path created by a trauma she never knew existed, which has shaped her entire life without her understanding why. The secrecy intended to protect her ultimately became the source of her lasting burden.

The appearance of a wooden doll missing one arm and one leg in Yayoi’s home introduces the central, disturbing symbol of the doll, which recurs across the files and links them together. Initially, Yayoi interpreted the doll as a personal metaphor for a lost twin, but its meaning becomes more sinister when the image of dismemberment recurs in File 3. Uki Mizunashi casually notes that her aunt’s baby was struggling after an operation, leaving it with a “festering stump of its left arm” (80). This parallel between a symbolic object and an infant who experienced dismemberment across decades transforms the doll from a private emblem of grief into a marker of a wider, ritualistic trauma. This symbol works in tandem with the motif of hidden rooms, such as the secret chamber in the watermill revealed by a moving wall. The doll itself was found hidden in a closet, another concealed space. These recurring elements of concealment and mutilation suggest a sinister, unifying pattern beneath the individual stories, hinting at a conspiracy that connects these strange buildings through a shared, violent history.