At 12:43 AM, the rooftop of the metropolitan general hospital was wrapped in silence. Ayano gripped the railing with both hands, gazing out at Tokyo's night skyline. Below her stretched countless window lights. The glow from high-rise buildings reflected off the night sky, casting a pale violet luminescence. Her long black hair, reaching her shoulders, swayed in the night breeze. In her deep amber eyes, exhaustion mingled with something else—another emotion, harder to name. Three years as a nurse. Tonight, she had just finished a sixteen-hour shift. Her limbs felt heavy, her shoulders rigid with tension. The navy scrubs beneath her white coat were wrinkled, and her nursing shoes were damp with perspiration. "...I'm exhausted." The whisper was swallowed by the wind. From the night shift through dawn, she had tended to patients without pause. Treating an elderly patient who had fallen. Managing IV lines. Bathing bedridden patients. An endless succession of tasks. She had come to the rooftop for a change of pace. The date had already changed. Even if she went home now, she would only manage a few hours of sleep. So she wanted—needed—just a few minutes of fresh air. Ayano closed her amber eyes. Her delicate, feminine brows drew together slightly. Her slender, graceful frame swayed in the wind. One hundred sixty-two centimeters tall. For a woman of the Sengoku era, that would be quite tall, wouldn't it—such a strange thought suddenly crossed her mind. She didn't understand why she was thinking such a thing. It made no sense. The night air pricked her skin. The cold wrapped around her narrow shoulders, her frame appearing almost ethereal in its fragility. "...I should go back." She released the railing. She was turning toward the stairs when it happened. Her vision warped. Without warning, the world bent grotesquely. The Tokyo skyline before her rippled like a reflection on water, wavering and undulating. The sensation of falling. Her body dropping. But where? Just before consciousness faded, Ayano saw something luminous. Like the moon. Like a star. A white light. It reflected on her left wrist. Then, darkness. When she opened her eyes, Ayano was lying on the ground. The smell of earth filled her nostrils. Sap and decomposing leaves—an ancient, musty scent. Wet mud clung coldly to her cheek. "...Where is this?" She pushed herself up. Her entire body ached. Blood trickled from both elbows, and her right palm bore fine scratches. Her nursing knowledge activated immediately. She must have fallen. Fortunately, there appeared to be no serious injuries. No fractures, perhaps. She flexed her fingers and bent her legs, conducting a quick self-assessment. But— When she looked around, Ayano's consciousness stopped for a moment. It was a dense forest bathed in moonlight. Towering trees filled her vision. Cedar or cypress—ancient trees with darkened bark surrounded her on all sides. White mist rose from their roots, wavering gently in the night air. No streetlights. No buildings. The distant sound was not traffic, but wind howling through the trees. And— The calls of wild birds. "What...?" Ayano's heart accelerated. She tried to maintain composure, but fear tightened around her chest. (Time travel? That's absurd.) It couldn't be. As someone with medical knowledge, Ayano understood that much. Yet the landscape before her existed nowhere in Tokyo. As she tried to stand— "Who goes there!" A low male voice cut through the darkness. Ayano's spine froze. Armed men burst from the grass. Five of them. Or six? In the darkness, she couldn't count. What they wore— Ayano's knowledge identified it instantly: the Sengoku period. Purple-indigo kimonos layered with armor. Spear-wielding soldiers. Swordsmen with blades at their sides. "Could this be... a period drama filming?" She wanted to believe that. But the soldiers' eyes held genuine intensity—the gaze of those facing true enemies. And more than that, the killing intent. Having worked with animals, Ayano understood their sharp instincts. She recognized it now. This was real. "What nonsense are you speaking? Are you a spy? Which clan do you serve?" The soldiers gradually closed the distance. Spear points glinted in the moonlight. "I... I am—" As Ayano tried to speak, one of the soldiers raised his spear. "Restrain her." The leader's command. In the next instant, something rough wound around both her arms. Rope. The Sengoku soldiers bound her with practiced efficiency. "Please, let me go. I'm a medical professional—" "Her speech is strange." One soldier smiled unpleasantly. Ayano's modern Japanese intonation bore no resemblance to the dialects of this era. "Where are you from?" "Tokyo. From the metropolitan general hospital—" They understood none of her words. All they grasped was: "woman," "strange language," "suspicious." "In any case, we bring her to the castle lord. This woman hides secrets." The leader pressed hard on Ayano's shoulder. Along a steep mountain path, Ayano was dragged forward. Her hands were bound with rope, her footing unstable. Her nursing shoes slipped repeatedly on the muddy ground. Only moonlight guided the treacherous path, where stones and roots jutted out everywhere. "Move." The soldier's voice was merciless. Ayano forced her legs to keep moving. The wounds on her elbows throbbed. But the resilience cultivated through nursing kept her body in motion. (Think. Gather information.) Even through fear, Ayano's mind worked. She observed her surroundings. Mountainous terrain. Tall trees. The sound of a valley stream. And— (Equipment I've seen in period dramas. Spears. Swords. The color of the kimonos. All of it—the Sengoku period.) She was beginning to accept her situation. If the impossible was happening, she had to acknowledge it as fact. Without surrendering to emotion, she had to think clearly about survival. "I possess medical knowledge," Ayano told the soldiers behind her. "I have information that could be useful to the castle lord." "Be silent. The lord will question you later." She was ignored. Dawn broke. The eastern sky shifted from pale violet to pale orange. That was when Akatsuki Castle came into view. It rose majestically on a hill at six hundred twenty meters elevation. A mountain fortress bathed in morning light. The main citadel, the secondary citadel, the tertiary citadel. White stone walls were stacked in layers, crowned with densely packed black wooden structures. There was no main tower—instead, a grand palace dominated the center of the main citadel. Ayano's breath caught slightly. "Akatsuki Castle," one soldier said. "Our lord's seat." The Shinonome Clan. Ayano would learn this name later. A minor domain in the southern Shinano region, nestled at the foot of the Kutsuki Mountains. Thirty-eight thousand koku in assessed value. Perpetually pressured by surrounding powers, yet sustained by this fortress's strategic position. But at that moment, Ayano knew nothing of this. She only felt the unbearable cold of a reality too impossible to comprehend—that she had truly slipped back to the Sengoku period. Ayano was brought to a room in the tertiary citadel's warrior quarters. A dimly lit space. The floor was wooden planks, the window positioned high, allowing only pale light to filter through. Beyond the door, at least one soldier would be stationed as a guard. Ayano settled into a corner of the room. The rope had finally been removed, but red marks remained on both wrists. By a nurse's assessment, they would not fade for days. (Stay calm. Think.) Ayano breathed deeply. She began using reason to bridge the gap between terror and reality. She had traveled through time. That much was certain. The mark on her left wrist proved it. A silver pattern depicting the moon and stars. The light she had seen just before the slip must have emanated from this mark. So what now? She was a nurse. She possessed modern medical knowledge. In this era— (Medical knowledge is a weapon.) Healthcare in the Sengoku period was surely primitive. The concept of sterilization would not exist. Understanding of infection would be inadequate. But Ayano had studied nursing for six years. She possessed that knowledge. "Survive." She whispered the word. Her voice was soft, yet carried absolute resolve. From beyond the window came the sounds of the castle—soldiers shouting, horses neighing, the noise of labor. All of it was foreign to her. Yet Ayano burned each sound into her memory, etched it into her consciousness. If she lacked knowledge, she would acquire it. Her amber eyes, in the pale room's dimness, glowed with quiet determination. To survive. To approach the castle lord and learn his true intentions. Ayano was taking her first step into this new era.