Corpses smell sweet. She learned that for the first time tonight. 　　　＊ Every time the bicycle's tires crossed a seam in the old asphalt, a faint vibration traveled to the delivery box on her back. Amemiya Aiko ran silently down "Kagerou Street" in the dead of night. The time was 2:17 AM. Miage Town, in the old district of Suirei City. A town of roughly fourteen thousand people that looked drowsy even in daylight, but at this hour its sleep ran deeper, more honest. The shopping arcade with its partially collapsed roof left in disrepair had streetlights that flickered out at a ratio of one in three, and cycling through it felt like passing alternately through light and shadow. Aiko didn't hate that sensation. There were no people. That alone made this town a safe place for her. Her appearance might have stood out slightly for a late-night delivery worker. Her straight black hair was cut short and neat at the ears, and her deep chestnut eyes held a quietness even in darkness. One hundred sixty-two centimeters tall, slender and delicate. Tonight she wore a simple white shirt and black slacks, with a black Fresh Line jacket over them. A small silver piercing in her left ear. And on the cuffs of her long sleeves, faint traces of tape remained—the marks of a habit of scribbling memos directly on her arm between deliveries, then peeling them off. （Room 6, lights are on again tonight） Her gaze shifted naturally as she rode. The third-floor apartment along Kagerou Street had dark windows again tonight. Aiko knew the mailbox had been overflowing for three days. Either away, or sick. Either way, if nothing changed by the day after tomorrow—and that's when her smartphone vibrated. A Fresh Line app notification. A new delivery request. Aiko exhaled softly. A sensation like relief, but not quite relief. In this app, she was nothing but "Delivery ID: A-0047." No face needed. No voice needed. Just deliver packages to the right place at the right time, and the ratings accumulated. Simple, clean, no human relationship noise. Delivery rating: 4.9 stars. She handled approximately thirty-five percent of the late-night shifts in the Miage Town area of Suirei City alone. Zero delays, strict non-contact delivery. Perfect record for a job where you didn't have to talk to anyone. She decided to forget about her university attendance rate of fourteen percent this semester. 　　　＊ The first three deliveries went smoothly. A one-room apartment in Miage Town, Block 2—fried chicken bento. Hung on the doorknob, photographed, completion reported to the app. An old apartment in Miage Town, Block 1—ramen and dumplings. Slid into the door pocket, photographed, completion reported. Fourth floor of a building along Kagerou Street—curry. At each delivery location, Aiko's gaze observed a little more than necessary. Two shoes of the same size lined up at the one-room apartment's entrance—someone had moved into a room that was supposed to be a single occupancy until recently. The mailbox at the ramen delivery location held two express letters that had just arrived today. The return addresses were from distant cities. Next to the door of the curry room, a child's drawing was taped up—a clumsily drawn house and person in crayon. Someone lived here. There was a life. Body heat. Because Aiko couldn't face people directly, she read only the traces they left behind. Unable to confront people, she saw only what they left. That was her "method of connecting with society"—not that she'd consciously thought of it that way, but looking back, that's what it was. After completing three deliveries, she returned to her apartment once. Room 206, Corpo Miage. A thirty-eight-year-old wooden two-story building, three thousand two hundred yen per month. On the wall of her 6-mat, 1K room hung a map of Miage Town pinned with thumbtacks, surrounded by hastily scrawled notes. "Wednesday late night, 8F garbage bags increased—roommate?" "302, recently refusing delivery placement→possible moving prep." It was less an observation record than an analysis notebook of the residents. She opened the refrigerator. A bento from Shokujidokoro Okame—a popular diner on Kagerou Street, a Fresh Line partner restaurant—two of them. Just arrived today. Aiko took one out and placed it on the table. She flipped her smartphone face-down, then turned it back over for some reason. The screen had accumulated notifications. An email from Suirei Public University—subject line: "Important Notice Regarding Attendance (Third Time)." Three messages from her mother. None marked as read. Aiko stared at them for a while, then flipped the phone face-down again. Instead, she opened a mystery novel. It was a habit unchanged since third grade. In books, every mystery had an answer. Every human action had a motive. What looked like chaos, when broken down, revealed orderly logic. Completely unlike real human relationships. Aiko had probably realized around that time that "mysteries were easier to deal with than people." （I don't know the outside world well enough to be dissatisfied with it） She looked up from the book at that thought. The wall map. Tiny stickers marking delivery locations. Herself, looking out at Miage Town's night through this window without leaving the room. She couldn't quite tell if that was unhappy. Only that not knowing itself made something in her chest ache faintly— Her smartphone rang. A new delivery request. Miage Town, Block 3, Sylphide Mansion, Room 704. Five hundred seventy yen with late-night delivery surcharge. Aiko closed the book and put on her jacket. 　　　＊ Sylphide Mansion was a twelve-story building, relatively new for this town. The entrance auto-lock could be opened with Fresh Line's dedicated code. Aiko operated it almost unconsciously as she stepped into the elevator. Seventh floor. The moment the doors opened, something was different. Aiko stepped into the hallway and tried to put that "difference" into words. It didn't work. The sound was quiet. The hallway fluorescent lights were functioning normally. The temperature, considering the difference from outside, was within normal range. Yet the air was different. The density was different. Room 704 was to the right after exiting the elevator, at the corner where the hallway ended. Aiko walked down the corridor holding her delivery box. The sound of her shoe soles on the linoleum floor seemed oddly loud tonight. Five steps. Ten steps. The door came into view. —It was half-open. Aiko stopped. According to Fresh Line's delivery regulations, hand-to-hand if someone's home, placement delivery if not. An open door meant someone should be home, but the intercom got no response. She pressed it again. No answer. "Um, Fresh Line delivery," she called out, her voice smaller than she expected. Not the voice of someone with social anxiety, but a voice suited to this space—if such a thing could be said. No response. Instead, something reached her nostrils. Sweet. Yet sour. Organic, with a faint hint of iron—a smell she'd never encountered before, yet it triggered something. Like overripe fruit left rotting in the kitchen at summer's end. But heavier. More human. （I shouldn't go in） Logically, that was right. A suspicious door, a strange smell, the dead of night. What a delivery worker should do was one thing—report "unable to deliver" through the Fresh Line app and leave. That was all. （But） Her feet moved forward. She pushed the door slowly. The hinge creaked softly. A hallway from the entrance, then a living room beyond. The lights were on. On the table, a Fresh Line container. It had been opened. And on the flooring, a man lay collapsed. A middle-aged man. Jacket removed, lying nearly on his back. Eyes closed. Not moving. For the first three seconds, Aiko's thoughts stopped completely. Three seconds is subjective—it might have actually been one and a half to two seconds. Regardless, there was an absolute halt. Not fear so much as blankness. Recognition couldn't catch up. Then, on the fourth second, something strange happened. Her vision sharpened. When panic reached its limit, something reversed. A sensation of emotions saturating and paradoxically freezing. Aiko experienced this phenomenon for the first time. Something inside her switched to "observation mode." She couldn't stop it even if she tried. The Fresh Line container on the table—fried chicken set meal from Shokujidokoro Okame. Opened, but the chopsticks hadn't been used. Actually, the chopsticks were placed beside the container, but there were no signs of eating. The tips of the wooden chopsticks weren't soiled. The window. Locked from inside. But the thumb turn—the lock mechanism—had fine scratches. New scratches. The metal still had a dull gleam. The man's rigor mortis. Only the jaw and neck showed early signs of stiffening. Rigor beginning in the jaw joint and cervical region appeared four to six hours after death. Which meant this man had died— （Between 8 PM and 10 PM） Aiko finally noticed she was trembling. Both hands shook slightly. The delivery box made a faint sound. But her gaze kept moving. Still reading the space. Terror and the impulse to reason tangled together in her body, and she could no longer tell which was which. （This isn't natural death） Three pieces of evidence. The scratches on the locked window. The untouched meal. The discrepancy between rigor mortis timing and the delivery request time. But there was something to consider first. Aiko pulled her smartphone from her pocket. Her fingers shook; she failed to unlock it twice. On the third try, she succeeded. She opened the phone app. 1-1-0. "Yes, police." The operator's voice was calm. It helped Aiko. "Suirei City, Miage Town, Block 3, Sylphide Mansion, seventh floor, Room 704." Her own voice was flatter than expected. Not suppressing emotion, but emotion was so overwhelming that only facts came out. If there was a moment when someone with social anxiety could make the most accurate emergency call, this might be it. "There's a person, apparently the resident, collapsed here. No response, and rigor mortis has begun." "Understood. We're heading there now. Please stay at the scene." The operator said. "…Yes." Aiko answered just that and hung up. 　　　＊ The fifteen minutes until police arrived were strangely quiet. Aiko sat in the hallway outside the door. Her back against the wall, knees up, delivery box set aside. From here she couldn't see into the room. Didn't need to. She'd seen enough. The hallway fluorescent light flickered faintly. A faint insect sound came from somewhere. From the seventh floor, she had no idea how it got in. （Stay calm） Even telling herself that, the trembling wouldn't stop. But her thoughts kept moving. Kept moving on their own. The room's layout, the window position, the table arrangement, the Fresh Line container placed at the left edge of the table. Why the left edge? A right-handed person eating would normally place it in front or to the right. Placed at the left edge meant— （Not now） Aiko closed her eyes. Now was time to wait. Not time to think. But her brain wouldn't listen. Police arrived fourteen minutes after the call. Two uniformed officers and, arriving slightly later, someone who looked like a plainclothes detective. Aiko stood up and waited by the wall. She couldn't look directly at the officers' faces. Her gaze naturally wandered between floor and wall. "Are you the one who called?" A young officer's voice. "Yes." "Fresh Line delivery worker on shift tonight?" "That's right. Fresh Line." She answered while looking at the wall. Not meeting eyes. It might be rude by the standards of someone with social anxiety, but it couldn't be helped. While explaining the situation when she found him, Aiko almost unconsciously added: "The chopsticks hadn't been used. The container was opened, but—" "…What do you mean?" "He died before