In the deep darkness before dawn, the sound of hoofbeats crushed the grass beneath them, echoing across the stillness. Harune had not been sleeping. In the corner of the makeshift shelter, bound by rope, her fingers traced the contours of the broken smartphone. An unconscious gesture. She needed to feel the artifact of the modern world, to confirm to herself that she was still Harune—that she had not been erased entirely. "What is that sound?" One of the bandits stirred awake. The others rose with him. The campfire burned weakly, casting no light beyond the hut's walls. Yet the sound drew closer. Hoofbeats. Multiple horses. The footfalls of armed soldiers. They approached in a rush. "Bandit suppression force!" Someone shouted. The bandits moved in chaos. Some gripped their swords and turned toward the door. Others bolted for the back. But it was too late. The door exploded inward. Splinters of wood scattered like rain. Through the breach poured soldiers in armor, one after another. Some drew tanegashira—matchlock guns—from their belts. Even in the tenth year of Eiroku, firearms had already claimed their place on the battlefield. "You are under arrest." A low, merciless voice cut through the darkness. The soldiers gave the bandits no time to breathe. They swept through them like a tide. Steel flashed. Screams tore the air. The smell of blood—iron and salt and something else, something that clung to the back of the throat. The battle ended in moments. Less than five minutes. The bandits were annihilated. Only two remained alive. The rest lay motionless on the ground. Whether they were dead or merely unconscious, Harune could not tell. They simply did not move. "Who are you?" A soldier approached her. His gaze fixed upon her with the cold precision of a merchant appraising goods. "What is your name? What were you doing in this shelter?" Harune trembled. A captive again. Simply traded from one captor to another. Yet these soldiers' eyes were different from yesterday's bandits. There was order here. Control. "I... I..." She spoke quickly, explaining how she had been taken prisoner, how the bandits had bound her with rope. But she said nothing of her origins. That secret could not be told. The soldiers exchanged glances. "We will bring her before the lord." Someone spoke. The lord—the daimyo who ruled these lands. The soldiers lifted her onto a horse with care. There was no violence. She even heard voices asking if she was injured. And so the horse turned toward Narumi. ────── Narumi Castle was larger than she had imagined. It rose from a hilltop, a fortress of stone and timber. The walls were built in perfect rows, and the keep stretched toward the sky. Below, the castle town clustered like a nest of insects. In the tenth year of Eiroku, such castles were still rare. But this was the age when Oda Nobunaga ruled Owari, when castle construction accelerated across the land. Yet this castle did not belong to Nobunaga. It belonged to Nobukatsу. That name—she had heard it from the bandits' whispered conversations. The younger brother, standing against his elder. The man who ruled eastern Owari. Harune was led into the castle. She was lifted from the horse, her wrists bound again with fresh rope. But she no longer thought of escape. A woman of unknown station was worth more alive than dead—perhaps worth something. She had to gamble on that. "We will bring you before the lord," the soldier said. She was guided deep into the inner palace, to a room where military councils were held. ────── The moment she entered, Harune's breath caught. The man seated there radiated an atmosphere that was far from ordinary. Twenty-seven years old. Sharp, refined features. Black hair cut short. His kimono was simple, but the arm guards from shoulder to elbow were crafted from fine steel. Yet what struck her most were his eyes. Expressionless. Eyes that revealed no emotion. And yet, beneath that surface, something fierce seemed to coil—a depth that suggested hidden intensity. This was Oda Nobukatsu. His gaze moved across her like a merchant's scales, weighing, measuring. From crown to sole, he observed her entirely. Under that scrutiny, Harune felt her body instinctively shrink. "Who are you?" His voice was low. Devoid of inflection. Merely factual, as though he were confirming a detail in a ledger. "I... I..." Harune forced the words out, trembling. Her name. How the bandits had taken her. How she had come to be here. But regarding where she had come from, why she wore such clothes—she answered vaguely. "Your origins are unknown, then." Nobukatsu murmured. "Yes. I am deeply sorry." Harune bowed her head. In that moment, Nobukatsu's hand struck the desk. The sudden sound made her flinch, and she looked up. "You have the face of someone with skill." Nobukatsu said this flatly. "Skill... sir?" "Speak. What can you do?" Harune's mind raced. This was an opportunity. If she said something of value now, she might live. If she said something worthless, she would die. But what could she say? If she spoke of modern knowledge, they would think her mad. Yet she had to say something. Then she remembered—the bandits' conversation from the day before. The Narumi plague. Last year, an epidemic had swept through these lands. Over four hundred people had died. "Boiling sterilization." The words escaped her lips before she could stop them. "...What?" Nobukatsu's eyebrow moved slightly. Interest flickered across his face. "Water heated by fire can prevent many diseases. Washing the hands. Isolating the sick. If such measures are taken, the spread of plague like last year's can be prevented." Harune spoke desperately, translating the epidemiology she had learned at university into the language of this age. The fundamentals of public health. The importance of sanitation. She spoke within the bounds of what he could understand. Nobukatsu listened in silence. His expression did not change. Yet something kindled in the depths of his eyes—a spark of something that had not been there before. "Interesting." He said this quietly. "Interesting, sir?" "I have never encountered a woman with such knowledge. Where did you learn it?" "That is..." Harune could not answer. The truth would mark her as mad. A lie might be discovered. Nobukatsu watched her silence. His gaze was sharp, as though he were reading the very thoughts behind her eyes. "You need not answer honestly. I am interested in your knowledge. That is all." He paused. "I will keep you in this castle as a candidate for concubine. Explain in detail your methods for preventing plague. If they prove useful, I will spare your life. If they do not..." He did not finish. He did not need to. The unspoken threat hung in the air like smoke—if you are useless, you will die. "Yes. Thank you, my lord." Harune bowed deeply. Her life was spared. At least for now. ────── She was taken to a building called the East Pavilion. Two rooms of six tatami mats each. Simple. Bare. From the window, the castle town spread below. The walls were wooden, and cold air seeped through the gaps. The floor was covered in tatami, and a small Buddhist altar stood against the northern wall. This was the quarters of a concubine candidate. "You are not permitted to leave except at mealtimes," the attendant said. A woman in her forties, with a severe face. "Yes." Harune no longer thought of escape. This was the only place where she could survive. Her knowledge might have value in this age. She had to wager everything on that possibility. When night fell, she was alone. The attendant brought her meal and departed. Rice gruel and salted pickles. The taste was not unpleasant. She gazed out the window. The lights of the castle town flickered in the darkness. What were the people down there doing now? Living their ordinary lives? Harune withdrew the broken smartphone from her pocket. It had remained hidden all this time. The cracked glass caught the light. *Will I be all right?* She whispered this to no one. There was no answer. Only the night wind, rustling the paper screens. The next morning, the attendant came. "Lord Nobukatsu summons you." Only one night had passed. Harune's heart raced as she made her way to the council chamber. Had something changed? Had he reconsidered? Nobukatsu was bent over documents. When she entered, he looked up. "Explain your methods for preventing plague in detail. Write them down. I have had brush and paper prepared." Harune took up the brush. Her hands trembled slightly, but she forced her thoughts into order. Modern knowledge, translated into the language of this age, into forms that could be executed here. Boiling sterilization. Encouraging hand washing. Isolating the sick. Managing water sources. As she wrote, Nobukatsu did not look at her face. He watched only the characters forming on the paper, his gaze sharp and unrelenting. "If you fail, your usefulness ends," he said coldly. "Yes. I understand." What else could she say? When she returned to her room, the attendant whispered to her. "Lord Nobukatsu is merciless, but he recognizes those with talent. If you truly prove useful, it is not impossible that you might survive in this castle." Was this encouragement or a threat? Harune could not say. She only looked toward the castle town visible through the window. There, many people lived. And perhaps—just perhaps—a woman with knowledge from another age could save their lives. But first, she had to earn Nobukatsu's recognition. That night, Harune repeated the details of plague prevention in her mind again and again. Knowledge she could not afford to forget. No—knowledge she had to remember. What she had learned at university, now to be applied to this age. And she thought of Nobukatsu's cold eyes. There was something hidden in those eyes. A secret. Why had he been able to control the east? Why had he stood against his brother Nobunaga? It was not merely strength. There was something else. Harune closed the window. Tomorrow, the work of preventing plague would begin. Success or failure. It all depended on whether her knowledge could take root in this age.