When she woke up, Sasaki Erika first counted the stains on the ceiling. In the six-mat room, there were seven marks from old water damage on the ceiling. Those brown patterns floating against the white ceiling cloth had been there for three years now. It was autumn of the year her parents separated. There had been talk of getting it fixed, but it had been left as is. Erika often found herself staring at these seven stains each time she woke. There was no particular reason. It was simply because there was nothing else to look at. But today was different. She woke as she always did, staring at the stains as she always did, when she noticed something was missing. Or more precisely, it wasn't missing—it was "absent." There was no temperature. That morning air quality—the faint discomfort that enveloped her body upon waking, the warmth of the blanket—all of it had vanished. It was like receiving external stimuli without a filter. Or more accurately— Erika sat up in bed. Her movements were mechanical. When her feet touched the floor, there should have been coldness, but the "sensation" of coldness wasn't there. Her brain held the information that "the floor should be cold," but the sensory experience that should accompany it was completely absent. She went into the hallway and descended the stairs. The aroma of miso soup drifted from the kitchen. Her mother, Minako, was preparing breakfast. It was an ordinary morning. The same scenery as always spread before her. "Good morning," her mother said. Her mother turned to face Erika. In that moment, Erika's brain detected one discrepancy. There was nothing in her memory. The warmth of the miso soup her mother had made, the brightness of the morning sun streaming into the kitchen—all of it was being "recognized." But the "sensation" that should accompany those things was completely absent. "Good morning," Erika replied. Her own voice sounded the same as always. But the drowsiness that should ride on that voice, the childish dependence on a parent—all those emotional colorations had been thoroughly erased. A bland response. As dry and flavorless as reading someone else's diary. "You look pale," her mother said. Her mother leaned in to look at Erika's face. In that moment, Erika observed her own expression objectively. When her mother spoke like this, she was worried. That was knowledge. But Erika herself couldn't "feel" anything in response to that worry. She could understand as data that her mother's concern was directed at her. But she couldn't receive it as an emotion. "I'm fine," Erika said. Another colorless, transparent response. It was then that Erika confirmed something was happening inside her. Breakfast was rice porridge. Her mother kept stealing worried glances at Erika's face. Erika ate the porridge. She drank the miso soup with tofu and seaweed. The taste was properly recognized. Salty, warm, the softness of the tofu—she understood it all. But the chain of sensory experiences that should connect them was severed somewhere. There was no feeling of deliciousness. No pleasure from the warmth. No disgust from bitterness. Everything was objectified. It was as if she wasn't eating, but rather observing her body consuming matter. It was then that Erika first tried to define it in words. "Emotional detachment." It might not be a medical term. But it seemed like the most accurate expression. Her memory was completely intact. She remembered being made to read a waka poem from The Tale of Genji in yesterday's classical literature class. She remembered some classmates laughing. But the "emotion" part of how she felt standing there—it was missing, as if someone had stolen it. "What? You're going to school? You're not feeling well," her mother said worriedly. Erika nodded. If she didn't move, more complex communication would be necessary. That would be more troublesome. The morning commute was as usual. The slope leading to Mikage Hama Minami High School was crowded with students. Shrill voices, footsteps, someone's laughter. All of it entered her ears as "sound." But Erika felt nothing in response to that noise. Everyone she saw on the commute was probably feeling something. Joy at the arrival of morning, or anxiety about school, or anticipation of seeing friends—such emotions probably rode on everyone's faces and voices. But Erika alone was outside that circle. Or rather, she was inside it, but separated by a transparent wall. Like a fish in a tank looking out at the world. The school building came into view. A rusted gate, a four-story building standing at the top of the slope. The sea was visible. Sagami Bay. Beyond the horizon. No matter how many times she saw it, that "sense of openness" she once felt there no longer existed. "Erika!" Takahashi Rina called out, waving from the top of the stairs. Her voice was bright. That brightness was probably genuine. Rina always spoke in that kind of voice. A loud voice, a resonant voice. The kind that carried from one end of the classroom to the other. She was the social type, the center of the class. Rina's hair was chestnut-colored and long, always tied in a ponytail. Her eyes were a bright brown, and when she smiled, they became crescent-shaped. Even in her school uniform, she looked somehow radiant. That radiance now seemed like something from a distant world to Erika. "Good morning," Erika replied. Rina approached and tapped her shoulder. It was a gesture of friendship. A greeting between best friends. Erika understood that. But she couldn't "feel" happiness at Rina's touch. Rina stared intently at Erika's face. "You really do look pale. Are you sick?" Rina asked, her brows furrowing. That furrowing indicated concern. Erika understood that as knowledge. But no gratitude, no relief, no sense of guilt arose in response to that concern. Rina was a good friend. She always worried about Erika. Normally, one should feel something in response to such consideration. "I'm fine," Erika answered. How many times would she repeat this word today? Rina said nothing more and simply pulled lightly on Erika's arm. A silent gesture to head to the classroom. That kindness only seemed to push Erika further away. When they entered the classroom, the school nurse, Honda Chizuru, happened to be in the hallway. She saw Erika's face, and her movements momentarily froze. Her gaze changed. Ah, this teacher had noticed something too. Honda Chizuru was in her mid-forties, a veteran school nurse who had been here for several years. From her experience seeing many students, she might have sensed Erika's abnormality. But Erika said nothing. If she said nothing, there would be no problem. The classes were painful. Whatever the subject, she had to repeatedly stare at the blackboard and copy something into her notebook. During that time, her classmates around her were feeling something while attending class. Boredom, sleepiness, tedium—or perhaps, even in a boring class, they felt the joy of being next to someone. Only Erika was unrelated to such things. The classroom was merely a physical space, the blackboard merely a black board, and the people around her merely objects producing sound. Within that understanding, Erika endured four hours of classes. After school, she headed to the Sumikawa Mental Clinic that her mother had booked. Five minutes south from the station. Third floor of a building. A white door with a plaque reading "Sumikawa Mental Clinic." When she arrived in the waiting room, Erika began counting the leaves of a potted plant. Not because she was particularly interested. It was just that she couldn't settle down without doing something. The plastic plant had exactly seventeen leaves. She could have made a note of that fact, but Erika accepted forgetting it. She felt no need to retain the information. "Sasaki Erika," the receptionist called. The doctor was a man in his late fifties named Sumikawa Yoshio. He wore glasses and spoke while facing his desk. His manner of speaking was polite, with a somehow detached quality. Ah, this doctor also viewed patients as "cases." That was probably natural. For a physician, patients were merely "cases." The doctor's gaze was always calm, with no trace of emotion. In that respect, Dr. Sumikawa and Erika were similar. "Your mother told me that starting this morning, you haven't been able to feel emotions," Dr. Sumikawa said. Erika nodded. "Is your memory intact?" he asked. "Yes," Erika replied. "Your appetite?" "Normal." "Your sleep?" "No problems." The doctor furrowed his brows. There was confusion in that furrowing. Erika observed it. It was natural for the doctor to be confused. This was a symptom not found in medical textbooks. "This is... unusual. For memory to be completely intact while emotions alone are lost—that's different from dissociative disorder. I'd like to ask you more details," Dr. Sumikawa said. The doctor asked various questions. Was there anything that came to mind? Had there been recent stress? Was there anything she could think of? Erika answered flatly. Her parents were separated at home. There were no major troubles at school. She had friends. She wasn't being bullied. There was no particular psychological shock. That contradiction seemed to confuse the doctor further. "I see... For a dissociative disorder, your memory retention is too complete. Normally, when such symptoms appear, fragmentation of memory should be observed. But in your case, your memory is complete, and only emotions are absent, which is..." Dr. Sumikawa trailed off and sighed deeply. The consultation time was drawing to a close. In the end, the doctor's diagnosis was vague. The possibility of dissociative disorder was suggested, but it didn't match existing cases. He said he would write a referral to another doctor just in case. But Erika couldn't quite understand what that would accomplish. It would only confuse the doctor. Erika's condition, which lay outside the map of medical knowledge, would probably be the same no matter which doctor examined her. On the way home, her mother kept looking at Erika's profile. There was clear worry in the direction of her gaze. Her mother couldn't understand this state of her daughter and didn't know what to do. That worry was justified. Any normal parent would think so. But Erika couldn't feel anything in response to that worry. "...If there's anything you can talk about, please tell me," her mother murmured. Fatigue mixed into her voice. She was tired from worrying about her child. That was understandable. But Erika had no words to return. Words existed. The words "I'm sorry for worrying you" came easily. But they were hollow. Words without emotion were merely combinations of sounds. "...Yeah," Erika answered briefly. No further words came. Her mother seemed to want to say something but ultimately said nothing. Silence fell between them. In that silence, Erika observed her mother's heart being wounded. It was a fact. Even knowing that fact, Erika felt nothing. With emotions absent, she couldn't empathize. After returning home, Erika lay down on her bed. The six-mat room on the second floor. Seven stains on the ceiling. From the window, the sea was barely visible. The water's surface illuminated by evening light. Its dark color. This sea too must have looked different once. Or rather, she hadn't "looked" at it—she had "felt" it. That sense of relief when viewing the sea. That strange sensation of being enveloped by something vast. It was gone. Erika gripped the bed sheets. She could feel the texture of the fabric. But there was no preference or aversion to that texture. Only an objective judgment of whether it was hard or soft. She wanted to cry but couldn't. She was afraid but couldn't feel the fear. Erika didn't know what disease this was. But one thing was certain—she had lost the proof of being human. If the essence of humanity was emotion, then Erika without emotion