At 7 AM, the alarm clock rang. Aoi Yuki opened his eyes slightly and searched for the source of the sound. An old digital clock on his nightstand. Red numbers displayed 7:00. He rose from his futon. At 174 cm tall, his black hair cut short stood slightly in the morning sunlight. His deep brown eyes still looked sleepy. His room was a typical six-mat apartment. The walls were thin, and he could often hear sounds from his neighbors and the floor below. But Yuki had grown accustomed to it. Sendagi, Bunkyo Ward. A district of Tokyo that retained the charm of the old downtown. The trees of Yanaka Cemetery visible from his window were stretching out new green leaves this season. Yuki glanced at them before beginning his routine. He showered, jolted himself awake with cold water, and slipped on a dark navy suit. His white dress shirt had grown a bit worn, but it was well-tailored. The suit suited his gentle-looking face perfectly. He paused in front of the mirror. There was a strange pattern on his left wrist. A geometric design drawn in thin indigo lines that had been there since childhood. Yuki himself didn't know what it meant. As always, it was hidden by his sleeve. He left the apartment at 7:35 AM. A seven-minute walk to Sendagi Station. The morning air was crisp and fresh with the season's characteristic coolness. He passed in front of the Maruetsu Sendagi store and headed toward the station. This was Yuki's daily routine. Every day, the same time, the same path. He boarded the Chiyoda Line. In the crowded car, Yuki gripped the hanging strap. Memories of friends from university briefly surfaced, but he redirected his attention to work. His indecisive nature meant he always took time deciding priorities. He got off at Kasumigaseki Station and walked. Soon the Akatsuki Tower came into view. The 22-story building was a symbolic presence in Chiyoda Ward's Uchisaiwaicho. Akatsuki Corporation—a mid-sized general trading company with annual sales of approximately 420 billion yen. Established in 1967. Operating on three pillars: energy resources, food, and IT equipment. Yuki had worked here for six years. As a general employee in the Sales Department II, he came to this place every day. Ninth floor by elevator. Several employees were already in the open floor. Department Head Toyama Tetsuya, 54 years old, was preparing for the morning briefing. The briefing was held every day at 8:30 AM. A routine. Yuki's desk was in the center of the window-side row. Documents accumulated from yesterday sat on top of it. "Good morning, Yuki." Someone called out to him. A colleague from the same cohort. Yuki replied, "Good morning." He was gentle and kind to everyone. That was his nature. At the same time, that nature would create complicated human relationships. The morning continued with desk work. Creating quotations, organizing materials for clients. Yuki concentrated on the work in front of him. But then he felt something. A voice calling his name from behind. "Yuki-san." A woman's voice. He turned around. No one was there. All his colleagues around him were absorbed in their own work. The sound of keyboards, papers being turned, the occasional voice of a phone call. But the source of the voice was nowhere to be found. "Must be my imagination," Yuki muttered. Was he tired? He shook his head and returned to work. 2 PM. He needed to deliver documents to the Management Planning Department on the 15th floor. That was higher up in the same building. He got in the elevator. Then a strange sensation struck him. A cold chill ran down his spine. The feeling of being watched. That was it. But he was alone in the elevator. He reflexively looked around, but there was nothing. Only his own face reflected in the elevator doors on the wall. "I must really be tired." He told himself this and headed to deliver the documents. The Management Planning Department had over a dozen employees including the general manager. The person who received the documents thanked him politely. Back on the ninth floor. As he headed to the men's restroom, he passed through a corridor. A passage to the emergency stairwell, a place with little foot traffic. The fluorescent lights shone coldly. When he came out after finishing, he felt it again. A gaze. He turned around. No one was there. "It's my imagination." This time, he concluded it for certain. It was fatigue. Yuki returned to his seat and continued organizing documents. That day's closing time was 6 PM. But Yuki stayed until 7 PM working overtime. He boarded the Chiyoda Line at Shimbashi Station and got off at Sendagi. He bought a bento box for dinner at a convenience store in front of the station. His usual bento. Fried chicken bento. 680 yen. He returned to his apartment at 7:47 PM. He climbed the stairs and entered his room. He showered, heated the bento in the microwave, and ate while watching TV. There was no particular program he wanted to watch; he had it on out of habit. At 10 PM, he lay down on his bed. He picked up his smartphone. LINE messages, emails—nothing in particular to do. To kill time, he opened an app. Then a notification caught his eye. 'Location Information Service: Your current location was confirmed by a third party (19:47)' Yuki's movements stopped. 7:47 PM. That was the time he was walking from Sendagi Station to his home. Exactly the time he had been walking that path just moments ago. "What?" Yuki sat up. He stared at his smartphone screen. He checked the location information settings. He looked at the app history. There were access records he didn't recognize. His location had been confirmed multiple times. His heart raced. A clear anxiety he had never felt before. Who. How. Why. Questions flooded his mind. Yuki reviewed the device and remembered something. When he had lost his smartphone years ago, as a security measure, he had installed a "location information sharing app"—a system that allowed others to know his location and allowed him to know theirs in return. It had been several years ago. He checked the app settings. Multiple accounts were registered. Family. Friends. And— "Shimizu Miyu." A junior from university years ago. They had reunited at a class reunion. At the time, she had been lost, and they had exchanged contact information. He had thought of her as just a casual acquaintance. For some reason, she had sent him an invitation to the location information sharing app, and Yuki had casually approved it. After that, they had exchanged messages a few times, but recently he hadn't been in contact with her. "But this... the location information 'confirmation'... the fact that it's displayed as being confirmed..." Yuki gripped his smartphone tightly. The location information sharing app worked on mutual access. For her to confirm his location, she would have to be sharing her location with him as well. In other words, there had been consent to share. "Why...?" He scanned his device with a security app. No abnormalities were detected. No viruses found. "A system glitch?" He muttered this. He connected his smartphone to the charger and turned off the location information service. He checked the security settings. He even deleted the location information sharing app. Normally, that would be the end of it. Even if something strange happened, he would have forgotten about it by the next day. But tonight was different. Yuki looked out the window. The night in Sendagi was quiet. Streetlights softly illuminated the town. An ordinary everyday scene. But the unease didn't disappear. He pulled the futon over himself. He closed his eyes. But he couldn't sleep. The day's sense of unease returned. The woman's voice heard from behind. The chill in the elevator. The gaze in the hallway. And the mysterious location information confirmation notification displayed on his smartphone. Were these really all coincidences? Yuki held the unanswerable question in his thin futon. At that very same moment, in another part of Sendagi, someone was gripping Shimizu Miyu's smartphone. The location displayed on the location information sharing app screen. It was the second floor of Corpo Sendagi. Aoi Yuki's room. That person—a woman named Shimizu Miyu. With short-cut hair and the same deep eyes as Yuki, she gripped her smartphone and whispered. "He made it home safely again today. I'm so glad." She was satisfied as she confirmed the moment the apartment's light went out. Only the reader knew—that Aoi Yuki's peaceful daily life had begun to quietly waver from today onward. And that the emotions swirling around him had begun to move, driven by the obsession of a woman named Shimizu Miyu. Was this something that could be called love? Or was it something else entirely? The answer to that question would be revealed in the days to come.