In the local history room, morning light slanted through the window at an angle. When 柏木信也 reached the top of the stairs to the second floor, the door was already open. There was a presence in the room. Within the same silence as yesterday, there drifted a density altogether different from the day before. On the desk, materials were arranged. The company history of Rokugatsu Construction—a thick cloth-bound spine with the company name stamped in gold foil—stood at the center, flanked by the chamber of commerce yearbook, photocopies of administrative documents from Mukurogi Prefecture, and microfilm editions of local newspapers, all positioned in chronological order. Countless adhesive notes clung to the pages, and pencil annotations ran in fine script through the margins of the table of contents. 小暮真帆 looked up at the sound of 柏木 entering. Her long straight hair, tinged with pale purple, swayed quietly beneath the fluorescent light. Her bright, clear green eyes fixed upon him. "Good morning." The greeting was polite, but without excess. Her words always took this form. 柏木 hung his coat over the back of a chair and surveyed the desk in its entirety. Just before closing yesterday, 真帆 had said she could prepare a list of holdings related to the Rokugatsu Construction company history and associated administrative documents. That alone had been the promise. Yet what lay before him now clearly exceeded the quantity a single library assistant could prepare alongside ordinary duties. 柏木 did not point this out. He felt it more important to receive precisely what that fact meant than to remark upon it. "Let us begin." With only those words, he pulled out a chair. ＊ The first thing he took up was the Rokugatsu Construction company history. A single volume containing sixty years from its founding in 1962 to the present. The front matter held a chronology, followed by records of successive projects, then pages of photographs. 柏木 first gazed at the photographs. There was a photograph of the dedication ceremony for Hinomori Municipal Hospital in the 1970s. The exterior of the ceremony. A ribbon-cutting. A line of applauding people. At their center stood a young man. Tall, dressed in a proper suit. No name was given, but the context made it readable—the Amagasaki family's patriarch of that time, or perhaps his successor. Standing as the region's guardian, gazing at the camera with pride. 真帆 looked at that photograph from the side. "My grandmother was born in this hospital." Her voice was quiet. Not an explanation, not a confession—merely the utterance of fact. "I am told it was a difficult birth. At that time, there was no obstetrics in that area. When this hospital was built, it saved the lives of many people." 柏木 did not lift his eyes from the photograph. 真帆 said nothing more. That light is real and that shadow is real are not contradictory. This understanding, taking no form in words, was quietly set down in the air between them. 柏木 closed the company history and opened the index at the back. The page for "A" was visibly more worn than the others. The corners of the paper were rounded, the surface faintly frayed. Evidence of how many fingers had repeatedly traced this single section. "Regarding the search frequency for Amagasaki—is there anything?" When he asked directly, 真帆's expression grew slightly troubled. "It is used every year in local history classes. Middle school students come here for research assignments." For only an instant, 柏木 allowed a wry smile to touch the corner of his mouth, then erased it. So in this town, middle school students look up the names of local luminaries in an index. It is embedded as a matter of course in their education. ＊ Through the morning, the two of them spread out the public records of Rokugatsu Construction in chronological order. Company history, chamber of commerce records, administrative bidding documents, local newspaper microfilm—they confirmed how the periods in which each source left the most abundant records connected to one another, and where they broke off. It was work conducted in near silence. 柏木 turned pages methodically, recording figures in his notebook. Beside him, 真帆 turned through the newspaper microfilm, searching for corresponding articles. It was collaboration with few words. After about an hour, 柏木's pencil stopped. He looked at his notebook. Numbers in hasty script lined the page. Records of public works contracts. Bidding results preserved in administrative documents. Completion years listed in the company history's "Project Achievements" section. There was a pattern. The period in which records were most abundantly preserved—the years when Rokugatsu Construction received many contracts and local newspaper coverage was active—was always followed by a brief gap. Sometimes a year later, sometimes two years later. Taken individually, it could be attributed to the convenience of record-keeping or a gap in coverage. But arranged together, the gaps repeated with regularity. The year following a surge in contracts. Before and after changes in leadership. It was too neat an alignment to dismiss as coincidence. When 柏木 looked up from his notebook, 真帆 was straightening her posture slightly before the microfilm reader. "柏木-san." The tone of her voice had shifted minutely. "In the local newspapers from the late 1980s, there are intermittent personnel notices for Rokugatsu Construction. Listed under the title of 'contract employee attached to the secretarial office.'" 柏木 stood and positioned himself beside the reader. On the screen, the personnel section of an old newspaper was displayed. A small article. Merely a few lines conveying the company's personnel order. "There is a pattern." 真帆's finger pointed to a single spot on the screen. "A woman's name appears in a personnel order exactly once. After that, the name never appears in the records again. No resignation order, no subsequent personnel notice, nothing." As 真帆 rewound the film and counted the instances, her voice fell silent with concentration. Her green eyes tracked the screen with unwavering focus. "Within what I can confirm, seven cases. From 1988 to the present." 柏木 did not move his expression. He did not repeat the number seven aloud. He only wrote it in his notebook. ＊ After a midday break, afternoon came. 真帆 brought from the depths of the archive a bundle of materials contained in cardboard boxes. The quantity required both her arms to carry, and when she stacked them on the desk, dust rose faintly. "What is this?" "Internal company publications from Rokugatsu Construction. 'Rokugatsu Newsletter'—a quarterly publication not included in the company history. It was donated to the regional library and has been stored without being organized." The company history is edited. Deliberately selected records arranged in deliberate order. But an internal newsletter is different. The weaker the editorial intent, the greater the gaps. 柏木 opened the cover of the microfilm edition. He confirmed the issues from the 1990s onward in sequence. Midway through, there was a page of recruitment notices. Introductions of new employees, announcements of mid-career hires, personnel transfers. A bland, formulaic page of standard text. But as he read further, 柏木's eyes stopped at a single point. In the recruitment notices section, a phrase appeared repeatedly. "Hired as contract employee attached to the secretarial office." Different years, different issues, different names. Yet the format was identical. It was used as a standard phrase, repeated again and again. 柏木 opened his notebook and wrote out the names of the four missing women. Names he had confirmed yesterday in 萩乃's apartment. One by one, he cross-referenced them with the recruitment notices in the 'Rokugatsu Newsletter.' Three of the four names appeared. Each was listed in an issue published three to six months before their disappearance, as a recruitment notice for a contract employee attached to the secretarial office. After that, they appeared nowhere—not in work records, not in resignation notices, not in any subsequent articles. They surfaced once in the record before vanishing. This structure perfectly overlapped with the seven personnel notices. Just as 柏木 was about to voice the meaning of this discovery, 真帆 had already begun to speak. "Records do not erase people." Her voice was quiet. Emotion was present, yet restrained. "People disappear first. Then the records are tidied away." It was an observation woven in the language of one who, as a librarian, had long witnessed the absence of materials. 柏木 looked at 真帆. Her green eyes received the weight of the discovery with precision. She was not surprised—she understood before surprise could take hold. To 柏木, this was the mark of the depth of this young library assistant's nature. ＊ It was past evening when 柏木 returned to his room at the inn "Oteasarai-so." Beyond the window facing the river, the ridges of Sourei-dai hill sank into the color of night. The line of the trees became an ambiguous shadow, dissolving into the sky. 柏木 opened his laptop and activated the database access rights that accompanied his contract with the Hagino Daily News. He performed a cross-search of articles from the past thirty years in the Mukurogi Prefecture publication area. Contract employee attached to secretarial office. Rokugatsu Construction. Missing. Runaway. He combined such terms, confirming each article that appeared. The individual articles were small. A few lines in a personnel column, a single paragraph in the local news section. Alone, they indicated no criminal matter. But when 柏木 arranged them chronologically, a different form emerged. 1993. 1998. 2004. 2011. 2017. The same pattern repeated at intervals of five to eight years. A recruitment notice appeared, and the subsequent record ceased. The local newspaper processed it as an individual case, the police closed it as a runaway, and the cycle waited to begin again. This periodicity was not the deviation of an individual. It was the practice of an organization. 柏木 looked up from the computer and gazed at the dark ridges beyond the window. What must be asked was not only the whereabouts of the four women, but why this structure had been maintained for more than thirty years. Who knew of it, who acquiesced to it, who profited from it. He felt the investigation, which had entered through the door of individual disappearance cases, now stretching toward the structure of the organization itself. He decided to narrow the next day's interview targets to the Amagasaki family proper. ＊ When 柏木 arrived at the library the next morning, 真帆 was already there. The materials on today's desk were different from yesterday's. A list of successive executives of Rokugatsu Construction and the organizational changes of the secretarial office arranged by era were spread before him. "Did you research this overnight?" "If one searches the holdings database, such things emerge." It was a modest answer, but 柏木 understood it was not meant to suggest the work was trivial. The search was a means; knowing what to search for was far more difficult. "The secretarial office was expanded and established as an independent department—" 真帆 indicated a single sheet. The organizational changes. "In the fiscal year following 天ヶ崎隆一郎's assumption of the chairmanship." 柏木 examined the organizational chart. The year the secretarial office was reorganized as an independent division reporting directly to the executive, shown there. It nearly coincided with the year the first recruitment notice appeared in his cross-search from the previous night. The two investigations complemented each other. Facts reached from separate sources began to form the outline of a single hypothesis. 柏木 gazed at that outline for a time. Then he turned to face 真帆. "There is one limitatio