The threatening letter was pinned to the edge of the reasoning board with a thumbtack. "Stop investigating." Just one line. Black text, printed out. The sender's field was blank. Aiko glanced at it once, then returned her gaze to the laptop screen. 5 AM. The reason she couldn't sleep wasn't fear—wasn't anger either. It was simply that she could see what came next, and her hands wouldn't stop moving. The FreshLine app kept cache data from delivery terminal devices locally for a set period. Normal couriers didn't have access to that area, but Aiko had noticed three months ago that the old API endpoint from before the app's version update was still active. She hadn't used it because there was no need. Tonight, there was a need. She typed the command. Logs scrolled. She specified 朽木隆之's terminal ID and pulled GPS cache data from the past three months. Data came back. Aiko scrolled while tapping her ballpoint pen cap three times. Northwest Mikage Town. The ruins of the old Mikage Textile Factory—coordinates that fell outside every restaurant in FreshLine's delivery area, outside every customer address. The terminal had stopped there three times during the blank period she'd identified in Episode Six. Minimum: 22 minutes. Maximum: 1 hour 4 minutes. Regular intervals, like someone meeting someone. Aiko picked up a red pen and wrote the coordinates on the reasoning board. Old Mikage Textile Factory ruins—12 minutes on foot from Kagero Street, site area approximately 18,000 square meters, three half-collapsed buildings. Surrounded by fencing but easy to enter, according to the world's memory that caught in her mind. The intercom rang. Exactly 6 AM. "[excited]Aiko! You awake!?" She knew it was Mina from the tone of voice. Aiko opened the door. Just five centimeters. Mina peered through the gap. Her mint-green twin tails swayed in the pale morning light. Two convenience store hot coffees in her hands. "[surprised]…Did you seriously work all night?" "Data extraction took time." "That's what people call not sleeping, usually." Mina held out the coffee. Aiko took it silently and turned her laptop screen toward the door instead. "…Factory ruins?" "The old Mikage Textile Factory ruins. 朽木's terminal stopped here three times." "You're going?" "At night." Mina's expression shifted into thought. "[surprised]…Why not during the day?" "People would be a problem." "But isn't a nighttime abandoned building normally scarier?" "Ghosts are easier to deal with than humans." Mina's face went blank for a few seconds, processing that answer. Then she whispered, "…Your fear standards are seriously off, Aiko," and tried to push the door open. Aiko widened it by three centimeters. Mina's face said "you're still not letting me in?" but Aiko sipped her coffee and turned the screen back. "Three minutes to explain. The correlation between GPS cache access logs and coordinates—" "[gentle]It's fine, you can explain while I'm inside." "I concentrate better through the door." "…I see." Mina didn't push. She stood in the hallway outside the door, sipping coffee while Aiko explained. GPS stopping points. Building structure. Correlation with the blank period. Three minutes, done. "[serious]I only understood about half of it." "Which part." "All the API and cache stuff. But I'm going, tonight." Immediate answer. (Fast judgment.) Aiko tried to process it as a variable in her reasoning—it didn't work. Mina's single word "going" didn't fit into any category on the reasoning board. The coffee was warm. ＊ 11 PM, deep night. The fence around the old Mikage Textile Factory ruins had rotted at the northwest corner, foundation and all, leaving a gap wide enough for one person to slip through. Aiko had already identified three entry routes a week ago from Google satellite photos and past trespassing reports. Enter from the least conspicuous north corner. "[scared]…We can actually get in here?" "Fence deterioration. Two or three trespassing incidents are reported monthly." "Hearing that makes it scarier." The interior was darker than expected. The building's steel frame blocked out the sky, and streetlight didn't reach. The moment Mina tried to turn her smartphone light to maximum brightness, Aiko reached over and turned down the brightness slider. "[serious]Light stands out. This much is enough." "…Your instructions are so detailed they're actually scarier." "Fear makes you careful." Mina whispered "that's true" and stayed one step behind Aiko. The second building. The structure closest to the GPS log stopping point. The metal door at the entrance had a padlock on the inside. Aiko circled the building. On the east side, what used to be an outer wall had collapsed, concrete rubble piled up. She could get inside through the gaps. "[surprised]Abandoned building navigation mode activated…" "I haven't activated anything." "No, you definitely have right now." They climbed over the rubble and entered the office ruins. Desk remains. A toppled shelf. Paper scraps scattered on the floor—all of it eighteen years old. Time left behind when Mikage Textile Corporation went bankrupt. But in one spot, there was a place cut off from time. Three cardboard boxes. Stacked against the wall, behind the desk remains. A padlock. New. While everything else was rusted and corroded, this lock alone gleamed dully. (She came regularly. Maintained it. No doubt.) "[serious]What do we do about the lock?" "We don't break it." "Open it without breaking it?" "We don't open it. We enter from the bottom." Mina's face went "huh?" Aiko crouched down and shined her flashlight at the box's bottom. There were scuff marks on the floor. The direction of the drag—the way the box had been moved. Working backward from that, she pulled the box so its bottom faced toward them, revealing a duct-taped bottom surface. "We peel off the duct tape and open from the bottom. The padlock on the lid is meaningless." Mina went silent for several seconds. "[laughing]…You're too much of a genius, it's frustrating." "Help me." The two of them carefully pulled the box out and peeled off the bottom duct tape. The contents appeared. ＊ Stacks of A4 documents. Files with index tabs. Hand-drawn correlation diagrams. Aiko read through them at high speed, shining the light. "Suirei City Urban Planning Division—Internal Memorandum." "Mikage Textile Corporation—Review Process for Additional Financing Application." "Financing-Related Personnel List (Confidential)."— Eighteen years ago. Mikage Textile's bankruptcy. The suspicion of fraudulent financing was "investigation halted mid-process," according to the world's information. But here, everything after that halt was recorded. Copies of memoranda. Approval stamps. Names lined up in the decision-making route. Her eyes caught on the hand-drawn correlation diagram. Seven marks in the diagram. Each with a name and address. Aiko cross-referenced them in her mind with the seven victim list. Match. Four cases—no, five. Five of the seven victims' names appeared in this diagram. All recorded as "financing-related personnel" involved in the fraudulent financing eighteen years ago. (Cover-up. Eliminating people who knew about the financing fraud, one by one.) The thought connected in a single line. At that moment, footsteps echoed from the entrance of the ruins. Mina's shoulder jumped. Aiko didn't move. One set of footsteps. Unhesitating gait. Someone who knew this building's structure. Flashlight beam cut through the rubble gap. "…I thought you'd come." 朽木隆之 stood there. The face she always saw at the desk in the back of FreshLine Mikage Town Station—the gentle smile, the thin platinum-white hair—but tonight he wasn't smiling. Just quiet, watching the two of them with calm blue eyes. Mina shrank her shoulders slightly. She thought she was about to be yelled at. "[serious]I can detect when cache data is extracted, as an administrator. I knew when you moved." Aiko stood in front of the cardboard box, watching 朽木. "[serious]Have you finished reading?" "…Five cases match." 朽木 set his flashlight on the floor and sat down on the ground in front of the box. He leaned his back against the wall and breathed quietly. "[serious]I'll start with why I quit city hall three years ago." ＊ 朽木's story wasn't long. He told only what was necessary, in order. He noticed the fraudulent financing suspicion while organizing documents at the Urban Planning Division—he found contradictions in the route. He reported it to his supervisor. The month after reporting, he became the investigation target instead. He was encouraged to resign. It was processed as "personal reasons." He copied all the evidence documents before they could be destroyed. He hid them here. He didn't leave Mikage Town to keep protecting the evidence. The transfer to FreshLine had no other reason. While searching for a window to make a report, victims started appearing half a year ago. "[serious]I realized it was a cover-up when the third victim appeared. I looked at delivery records and saw all the victims were FreshLine users. But I couldn't tell you everything." "Why." "[serious]I didn't want to put you in danger. I knew the threatening letter had come." Mina said in a small voice, "…You knew?" "[serious]Traces of the sender's activity appeared in the data. But I had no way to stop it." While listening to 朽木's story, Aiko thought about who sent the threatening letter. (朽木 was trying to protect the evidence. The threatening letter came from the side that feared their approach. There's no reason for 朽木 to send it. If he had, he wouldn't come to the ruins like this and talk.) Her reasoning converged to one point. "The real culprit is a relative of the victim in Room 704?" 朽木's eyes narrowed slightly. "[serious]…How did you figure that out?" "In the correlation diagram, only the Room 704 victim is listed as the financing executor. The other victims were on the knowing side. If you eliminate the executor, the full picture of the fraud becomes unclear. But the executor had an accomplice." "[serious]That accomplice's name and current address are in the file at the bottom." Aiko pulled out the file. Name and address. Within Suirei City. About two kilometers from Mikage Town. "[serious]I've been looking for a place to release this for three years." Aiko took out her smartphone. ＊ The message to 瀬尾 was brief. Name. Address. 朽木's testimony and the document contents. Bullet points. 瀬尾's reply came four minutes later. "Applying for warrant. Can you secure the original documents?" "朽木 will bring them." "…Understood." That was all. Very 瀬尾. An hour later, 朽木's smartphone rang. A call from Suirei Police Station Criminal Division. The warrant had been issued. "[excited]We did it!!" Mina's voice echoed off the ruins' ceiling. Rusted steel beams carried it far, reverberating. Aiko remained against the wall, unmoving. (Five cases matched. But there were seven.) It was resolved. But she hadn't saved all seven. That fact sat in the center of her chest with the same weight as the sense of accomplishment. Not that she couldn't process it—just that it was there. "[gentle]If you hadn't come, I think I would have ended without being able to report this." Aiko thought for a moment before answering. "I didn't make it in time for all seven." "[gentle]…There was a part you did make it in time for." Aiko didn't answer. 朽木 didn't push. Mina read the space between them and went quiet. The ruins' ceiling had a hole. Through the gap in the collapsed metal plate, night sky was visible. Stars. Stars that were barely visible from Kagero Street in Mikage Town, but visible from here. Stars that had gone unseen for eighteen years through the ceiling's hole. The three of them looked up at that hole in turn. No one said anything. But the silence wasn't heavy