The third floor of the office was dimly lit even in the daytime. Light filtered through the window, cutting diagonally across the floor, and papers were lined up in its path. Kashiwagi Ren knelt on the floor, examining printed damage records one by one. Data from the past six months that Haruka had pulled from the storage room. The dates of cancelled live performances, the times when interference occurred, which equipment had stopped. Ren transcribed each detail into a notebook while entering them into a spreadsheet on the terminal. Five days since the transfer. Since staying on the third floor of this office, Ren's life had been consumed almost entirely by this work. When tired, they'd take a short nap on the simple sofa in the break room, then return to the records. When hungry, Haruka would bring something up from the first floor. (There's a pattern.) Ren arranged numbers along the edge of the notebook. When organizing the days and times when interference occurred, a certain tendency emerged. Between 72 and 96 hours before the actual live performance. And every time, the audio equipment's network connection was being routed through. All three incidents used the same method. "So the next one is in three days." Ren murmured to themselves while looking at the calendar. The Shione Ward Shopping Street Mini Live. An event where 765 Pro's idols were scheduled to perform. A small outdoor stage live, about 100 people. But if the current pattern was correct, this would be the next target. Going downstairs to the office space on the second floor, Ren found Haruka with a schedule book spread open. She tilted her head slightly when she saw Ren. "Did you figure something out?" "Probably. The noise is set up every time between 72 and 96 hours before the actual performance. I think the next target is the mini live in three days." Haruka's expression changed. Surprise, then immediately a serious face. "...Understood. Then let's think of countermeasures." It was an answer without hesitation. She didn't say "Really?" or "What should we do?" She simply said "Let's think of countermeasures." At that speed, Ren's eyes narrowed slightly. (They haven't given up yet, have they.) On the office wall's whiteboard, the words "Live Cancelled ×3" still remained. The SNS feed continued to spill out critical posts even today. Yet Haruka's response came without a second's delay. Something in Ren's chest solidified just a little. --- By afternoon, Ren had moved to the lesson studio on the first floor. They needed to write the program for the frequency filter. Ren connected the terminal to an outlet in the corner of the studio and began writing code. Detect and block the specific frequency band used by the noise. No impact on other audio ranges. In theory it should work, but actual tuning to match the audio equipment was necessary. Beyond the mirror-lined wall, Haruka was practicing. At first, Ren hadn't paid attention. But noticing the same song repeating the same section over and over, Ren stopped working. Haruka steadied her breathing and sang again. The same phrase. She stopped again. Took a deep breath. Sang again. It looked less like she was trying to make it perfect, and more like she was trying to overcome something. Even from a distance, it was clear her body was slightly tense. Ren kept watching from the corner of their eye, terminal still on their lap. After a while, Haruka stopped practicing and wiped her face with a towel. Their eyes met. "You were watching?" "Yeah." "Was something off?" Ren thought for a moment, then asked directly. "Why can you try so hard?" Haruka paused for a moment. She held the towel in both hands, her gaze falling to her feet. It seemed like a question that didn't have an immediate answer. Then, slowly, she looked up. "When I sing, if someone smiles... I become happy too. I think that's something really wonderful." It was an unadorned answer. Ren couldn't say anything in return. (I started studying music production because...) Thoughts moved in Ren's head. Because I thought if I could create someone's stage, I could have meaning even without a place to belong. That was the reason. Rather than wanting to make someone happy, they had been searching for a reason for their own existence. Haruka's answer wasn't that roundabout. She wanted to see someone's face. If that face looked happy, she became happy too. That was all. Ren thought—there really are people who can say things this straightforwardly. Ren's gaze returned to the terminal. Their head was warming slightly. --- It was when the lesson was in its middle stages. All the lights in the studio went out. After a moment of darkness, sound began coming from the speakers. Not music. High-frequency noise that pierced the ears. The studio walls trembled. The screen on Ren's terminal flickered for a moment. "—!" Haruka pressed both hands to her ears and crouched down. Ren was already running. The audio control panel at the edge of the studio. Ren assessed the situation in a second. They'd been infiltrated through the network—couldn't stop it from software. Then do it physically. The main power breaker at the bottom right of the panel. Click. Three seconds later, the studio went silent. In the darkness, only the sound of Haruka's breathing could be heard. She was trembling. Standing still, Ren called out toward her in the dark. "You okay?" There was a pause. Then Haruka seemed to stand up. "...I'm fine." Her voice was trembling slightly. She wasn't fine. But Ren said nothing. If Haruka needed to say that, then she should be allowed to say it. The emergency lights began glowing red. In that light, Ren immediately opened the terminal. They pulled up the system diagnostic logs. There was a Void Sign. The same encrypted marker had been carved into the equipment logs this time too. But that wasn't all. This time, the signal's angle of incidence and delay data remained. Ren looked at those numbers and calculated in their head. (The source is... within Shione Ward. Within a 2km radius.) It could be narrowed further. But with the current information, this was the limit. Ren spoke quietly, still looking at the terminal. "This is a warning for the mini live." "A warning?" "They're wearing down our nerves before the actual performance. Showing us they'll do it at the venue next. The noise is in Shione Ward. Right nearby." Haruka was silent. In the red emergency light, she was looking straight at Ren. Ren couldn't tell if she was scared or angry. "...Can you come up with countermeasures?" "I'll try." --- The morning of the mini live was cloudy. The outdoor stage at Shione Ward Shopping Street was a small one set up in the Komachi Street plaza. White curtains, four lights. The equipment was compact, but it had a proper sound system. Ren arrived at the side of the stage two hours before the live started and checked the audio equipment connections. They connected a sub-notebook and installed the frequency filter program. If the noise's interference signal used a certain frequency band, it would be blocked immediately, without touching any other audio range. The design had been finalized with a final check last night. "Work," Ren said quietly, confirming the settings. The waveform monitor activated. No problems. People began gathering in the shopping street from morning. Probably customers who'd seen the mini live announcement—mothers with eco-bags and what looked like student pairs gathered in the plaza. A few people had already claimed spots in the front space. (At this scale, it should reach properly.) Ren walked once between the stage and the audience. Confirming the distance. Whether this scenery could be protected depended on Ren today. The live began. Haruka's voice resonated through the shopping street. Ren stood with their back against the concrete wall at the side of the stage, watching the waveform monitor on the terminal. The green line wavered. Normal audio frequency waveforms. Seventeen minutes in. A red spike ran across. For just a moment, the equipment trembled. The monitor's waveform began to distort. But the next instant, the filter activated. Only the problematic frequency band was blocked. The sound coming from the stage remained undisturbed. Haruka's voice reached the plaza as it was. Ren exhaled. They looked at the stage. Haruka was there in the lights. Different from watching from the side while working. Looking straight ahead, directly. Her bright crimson hair bounced the light from the illumination. Her orange eyes were facing forward. Singing toward the audience, face raised. Ren couldn't believe it was the same person who'd been in the studio next to them. When you stand on a stage, something changes. That's something that happens to people. Ren understood that from studying music production. But understanding it in your head and seeing it before your eyes were different things. (I want to protect this.) Those words appeared in Ren's mind. They didn't know why. There was no logical reason. But that emotion was definitely there. Ren acknowledged it and thought nothing more. The live ran to completion. --- Cleanup began. Staff carrying equipment, fans preparing to leave. The plaza slowly grew quiet. Ren returned to the side of the stage and was re-analyzing the source data from the terminal. If they added today's interference signal incidence data, they might be able to narrow down the source a bit more. Footsteps approached. "It's thanks to you, Ren." Haruka said this while gripping Ren's hand tightly with both of hers. Ren's thoughts stopped. Her hand was warm. That was all Ren could think about. The terminal's analysis screen was in their field of vision, but the numbers meant nothing. Their head was completely blank. Ren hurriedly pulled their hand away. Their gaze fell to the terminal. Their face was hot. They could feel it themselves. This was bad. Haruka either didn't notice or simply turned toward the plaza. "All the fans who came today had such nice expressions on their faces." Ren answered after a beat, still looking at the terminal. "...Yeah." They could tell their voice had dropped slightly. Evening air flowed through the shopping street. The sound of store shutters closing, a car running in the distance. Today's mini live had been a success. The filter had functioned. That much was certain. But. (I've narrowed down the source. But I still don't know who it is.) Within a 2km radius of Shione Ward. Right next to the 765 Pro office, the noise was there. They already knew today's live had ended. They were probably already thinking about their next move. Tonight's success wasn't a reason to stop the next attack. Ren closed the terminal screen. Street lights along Komachi Street began lighting up one by one.