There was a gap in 朽木隆之's data. That fact continued to smolder quietly somewhere deep in 藍子's chest, even after she'd posted a new memo on the deduction board and gone to sleep. A trace from one case. Nothing more, nothing less—or so she'd tried to convince herself. But every time she woke, the question surfaced first: "But why is there a gap?" Morning light filtered thinly into Room 206 of Corpo Mikage. Slanted sunlight sliding through the curtain gap illuminated the memo papers stuck to the deduction board in white. "朽木隆之 → Suirei City Hall Urban Planning Division → Retirement Reason Unknown → Transferred to FreshLine." "Missing Data → Three Days Before/After Estimated Death." Red seals and hastily scrawled arrows. 藍子 sat in her desk chair, staring at the CSV data she'd printed out last night. She tapped the ballpoint pen cap with her finger. Three times. Then it stopped. (I can't move forward without getting the source of the data.) She knew that. But the resistance to re-contacting 朽木 and the suspicion that the data had been manipulated tangled together in her thoughts, refusing to untangle. The intercom rang. Once. 藍子 didn't move. Twice, three times—and before the fourth ring, her smartphone vibrated. A message in the FreshLine app chat. From "ねこたみな☆." "藍子さん!! You awake!?!?" Then: "The detective contacted me!!!!!!!!" No emojis. It was rare for ミナ to skip emojis. 藍子 read the message, then read it again. (Detective.) Scrolling through the chat, there was a forwarded message from ミナ. A message in business-like language that had come through FreshLine's delivery staff contact network—a channel normally used for work communications. "To Delivery Staff 雨宮藍子: We have confirmation matters regarding your recent delivery. Would it be possible for you to contact us at your earliest convenience? Suirei Police Station Criminal Investigation Division, Detective 瀬尾誠司." 藍子 analyzed that route for three seconds. (Coming through FreshLine's contact network, leaving no record. Not an official summons, and not using my personal contact information. The intent to minimize traces is readable—) The intercom rang again. This time continuously, restlessly. 藍子 sighed, then stood. She opened the door. Just five centimeters. ミナ stood in front of the door. Her mint-green twin tails swayed around her shoulders. Her golden eyes were wide open. "[excited]The detective!! It's the detective!! Isn't that amazing!?" "Your voice is too loud." "But it's the detective!? It's like a drama!?" "I've seen them." "You should reply, right!? Let me borrow your phone for a sec—" The moment ミナ reached out her hand, 藍子 silently grabbed her wrist. Gently, but firmly. ミナ's movement stopped. "Huh?" 藍子 pulled her smartphone to her side and began typing a response. ミナ, still held, peered down at 藍子's hands with a bewildered expression. The message she sent read: "Mikage Town Police Box Front, 3 PM today. I can only respond if I'm outside the box. —雨宮藍子" ミナ read the screen and her mouth fell open. "[surprised]You... set conditions with the police?" "I can't go otherwise." It was a short statement. But ミナ seemed to sense the weight contained in that single line. The smile forming at the corner of her mouth softened instead. Not mockery, not surprise—just an expression that said "I see." ミナ said nothing. She simply nodded slightly and asked, "Can I come with you?" 藍子 thought for a moment, then answered. "...Yes." 　＊ The Mikage Town Police Box at 3 PM stood quietly at the east end of the shopping district. Just before the Kagerou Street arcade ended, next to an old vending machine, a small building. A plate reading "Suirei Police, Mikage Town Police Box" was affixed to the glass window. In the alley in front of the box, a man stood in a waiting posture. Around forty. Dark brown hair, short and neatly trimmed, with white beginning to show through. Wearing a suit with a tie, arms crossed in front of him. Tall, solidly built. Black eyes, sharp—but not merely cold. There was a warmth in their depths, a certain kind of light. The type of eyes that belonged to someone like that. In civilian clothes, but with the bearing of a uniform. A man who embodied the profession of "detective" with his entire body. "[serious]...You came." A low, calm voice. 瀬尾誠司—Suirei Police Station Criminal Investigation Division, Sergeant—nodded once, looking at 藍子 and ミナ. 藍子 placed her hand on the police box's sliding door. And pulled it open just five centimeters. From the side, 瀬尾 said, "Would you come inside?" "[serious]This is fine." 瀬尾 paused for a beat. "...There are chairs inside." "Outside is easier." "I see." ミナ watched the exchange from slightly behind 藍子. She whispered, "Is there precedent for this...?" but neither of them answered. 瀬尾 took interview documents from his bag. A4-sized paper with a printed form. And—without hesitation, he slid it through the five-centimeter gap in the door. "Could you sign this?" 藍子 thought for a moment, then extended only her right hand through the gap. She took the pen, pulled the document inside, signed it, and returned the pen and papers through the gap. An elderly couple passing by stopped, bewildered, at the sight. The police box door was open just five centimeters, a hand extending through the gap to sign documents. The detective received it with a serious expression. After the elderly couple left, tilting their heads, ミナ quietly tugged 藍子's sleeve. "[whispers]...You're like a famous detective." 藍子 didn't answer. She kept her grip on the door handle, facing forward. The interview began. 瀬尾 opened his notebook and began reading the records from the time of the report. His tone changed—from the stiff formal language of moments before to the quiet tone of someone confirming information. "At the delivery to Sylpheed Mansion Unit 704, the front door was locked from inside, but the thumb turn showed rotation marks in a position inconsistent with normal use. Post-mortem rigidity was concentrated in the right upper limb, contradicting the body position. Dishes remained unused, and there were no food traces inside the microwave—" As he read, 瀬尾 looked up. He looked at 藍子. "...Your report was abnormally accurate." Beyond the five-centimeter gap, 藍子's chestnut eyes were directed toward 瀬尾's left shoulder. "[serious]It didn't add up, so I recorded what I saw." "Didn't add up, how?" "The way it was locked, the position of the rigidity, the state of the dishes—the three together don't form a coherent accidental death." 瀬尾 wrote something on the document. Without looking at his hand, still looking at 藍子. "It took our criminal investigation division a week to reach the same conclusion." "I think it's a matter of experience." ミナ started to whisper, "Experience with what..." then stopped. 瀬尾's reading continued. Each time he confirmed a point 藍子 had raised, his tone shifted slightly. From the voice of a detective cross-referencing information—to the voice of someone trying to verify something else. ミナ noticed. She gently tugged 藍子's sleeve and whispered in her ear. "[whispers]The detective's getting serious." 藍子 didn't move. She gripped the door handle slightly tighter. 　＊ "—Those contradictions," 瀬尾 paused. He glanced left and right down the alley in front of the box once. The edge of the shopping district. Few people passed through at this hour. The elderly couple was gone. Only the low hum of the vending machine sounded. "Are common to all seven suspicious death cases that occurred in the past six months." Silence fell. For three seconds, 藍子 was completely still. The hand gripping the handle, her gaze, even her breathing—there was no other way to describe it than "stopped." ミナ saw it and looked at 瀬尾. She whispered, "She's thinking really fast right now, please wait a moment." 瀬尾 straightened his posture and said, "...Understood." This strange frozen tableau—a detective standing rigidly in front of a police box in silence, a woman lost in thought inside a door opened just five centimeters, and a mint-green-haired girl quietly explaining the situation to the detective—had a comical appearance that belied the weight of the air flowing through it. Seven cases. That number connected with another number in 藍子's mind. The gap in 朽木隆之's data. Three days. One case. If that was—part of a chain of seven connected incidents. 藍子's thoughts reorganized with an almost audible click. A piece fitting into its exact place—that sensation. But this time, recognition of scale came before relief. What she'd thought was one case was one link in a chain of seven—that falling sensation. "[serious]...Is there the same gap period in the delivery records for all seven cases?" 瀬尾's eyes narrowed. "How do you know that?" "The data 朽木隆之 provided had a gap. Three days before and after the estimated death." 瀬尾's expression changed slightly. It was his eyebrows. They drew inward just barely—that momentary reaction, 藍子 didn't miss. Something unintentionally leaked when 朽木's name was mentioned. (朽木 knows something.) 藍子 released the door handle. She opened the door. This time fifteen centimeters. Not five—fifteen. Half of 藍子's face emerged into the outside light. Her chestnut eyes looked directly at 瀬尾's eyes. ミナ made a small sound. "Ah." The "ah" she would later describe as "藍子さん opened the door on her own." "You reacted to the name 朽木." 瀬尾 didn't answer. But he didn't deny it either. Seconds passed. 瀬尾 closed his eyes once. Then opened them. "...Let me tell you something." 　＊ What 瀬尾 began to tell was concise, and therefore heavy. Seven suspicious deaths. The first six months ago. All single-person households, all FreshLine users. Within Suirei Police Station, Police Chief 堂島芳正—57, a man who prioritized his relationship with the mayor—had ordered all cases processed as "isolated deaths from natural causes." Warrant applications to continue investigation were buried internally. "[serious]I'm pursuing this case alone within the division. But I have no official investigative authority. No materials I can use as evidence." ミナ whispered, "That means..." 瀬尾 continued. "The fact that you remained on external records as the discoverer of the seventh case is why I judged now to be the only opportunity. Normally, this kind of cooperation request would be unthinkable." He paused. "But—what you saw was real." The tone, rigid to the point of stubbornness, functioned in this moment as desperation. That desperation of an inflexible person still trying to move forward. 藍子 traced the edge of the door with her finger for a while. The old painted wood grain was rough. "[serious]What's the point of cooperating?" "I can serve as the window that turns your deductions into evidence. Police internal routes and external observation—if we can connect those, there's a possibility it won't be buried." While 藍子 was thinking, ミナ moved. She gently grasped the edge of 藍子's sleeve. Not pulling, just touching. Her golden eyes looked at 藍子's profile. "[gentle]藍子さん, let's do this together." A small voice. But clearly heard. 藍子 looked down at her arm once—at ミナ's fingers gripping the edge of her jacket. Then returned her gaze forward. "Show me the delivery records for all seven cases from the police records. That's my condition." 瀬尾's expression moved. "...That would mean providing police internal data to an external party." "I know." "By regulation—" "I know." 瀬尾 fell silent. 藍子 said nothing either. Only ミナ felt the silence flowing between them. Neither had said "yes." But neither had said "no." Something—the atmosphere of an incomplete agreement—quietly filled the afternoon air in front of the police box. The vending machine made a low whirring sound. "[serious]...I'll think about it." "I won't decide immediately either." "That's acceptable." 瀬尾 closed his notebook. He bowed once and walked deeper into the al