The novel begins as Uketsu’s quest to understand the mystery behind the Tokyo house. Uketsu and Yanaoka know that something is terribly wrong but feel that their ignorance of architecture prevents them from uncovering the truth on their own. While Kurihara’s expertise enables Uketsu to recognize the full strangeness of the house, it also comes at the cost of entertaining Kurihara’s morbid speculations. From then on, the novel becomes a balancing act, as Uketsu’s curiosity wrestles with the possibility that he may learn more than he would like to know. More than that, however, the novel suggests that the full truth may simply elude Uketsu entirely, making the curiosity that Kurihara has sparked a hunger that can never be satisfied.

Indeed, while Kurihara’s speculations sometimes point Uketsu in the right direction, they can also be wildly off the mark. In Chapter 1, Kurihara proposes that the people in the Tokyo house are contract killers. In Chapter 3, he suggests that Yuzuki’s father saw Yoichi as a threat to his own family’s financial stability. Both theories are later refuted, casting doubt on Kurihara’s broader ability to intuit the truth from evidence like the floor plans. For instance, at the end of the novel, he suggests that the Seikichi branch of the family has instituted its own counter-ritual to decimate the Soichiro branch. This idea could open up an entirely new line of investigation, but it is unclear whether this theory is any more credible than those that Kurihara has previously proposed and discarded. Kurihara himself frequently stresses that his interpretations are mere speculation, framing the investigation as an intellectual exercise in deduction rather than a committed attempt to discover the truth.

For Uketsu, though, the point is not to imagine what could be but rather to determine what is. Uketsu consequently begins entertaining other ways to learn the truth about the house, from writing an article to crowdsource clues to visiting the Tokyo house, all to bring Kurihara’s theory out of the realm of speculation. However, his efforts to uncover the truth frequently run up against the limitations of the evidence. Material documents like floor plans are open to subjective interpretation, but witness testimonies can be unreliable, whether due to conscious deception or simple misunderstanding. For instance, Yuzuki’s revelations illuminate some of the hidden truths about the Tokyo and Saitama houses, but the fact that she was a child at the time of events like Yoichi’s death somewhat undercuts her reliability. Moreover, the investigation stretches ever further back into the past, meaning that the events under consideration have passed through multiple retellings and thus multiple layers of potential bias. 

Kurihara’s final theory about Yoshie exemplifies the problem: As he points out, she is a member of the Soichiro branch by marriage but a member of the Seikichi branch by birth and thus may have unstated reasons for telling the story as she does. By this point, however, Uketsu has stepped back from his role as investigator. When he accompanies Yuzuki to confront Yoshie, he is no longer an active seeker of truth, but a passive observer of the Katabuchi family drama. In witnessing the family’s reconciliation, Uketsu finds an emotionally satisfying resolution that does not hinge on pursuing every possible lead as far as it can go. Thus, when Kurihara proposes his theory, Uketsu becomes dizzy rather than excited. In the Afterword, Kurihara complains about Uketsu’s omissions, but these speak to Uketsu’s decision not to complicate the narrative any further. He chooses to stop telling the story because he understands that the full truth will never be known and that further attempts to uncover it will only lead to frustration.