Harune, a modern woman, is suddenly reborn during Japan's Sengoku period in the year 1570. Caught in the chaos, she is captured by the ambitious warlord Oda Nobunari and brought to his domain as a concubine candidate. Despite Nobunari's reputation for coldness and cruelty, Harune uses her modern knowledge to solve the region's problems—preventing epidemics with medical knowledge and revolutionizing agriculture through strategic planning. Gradually, she even captures the heart of the stoic warlor
Sengoku Love Prison ~ Kept by Ruthless Warlords ~ - Encouraging Handwashing and Isolation Facilities: The Battle to Contain the Epidemic
Three days had passed since Harune procured the medicinal herbs from Isuke.
Since that day, Harune had been making the journey to Jouenji Temple without fail. From the eastern quarters of Narumi Castle down to the castle town—a walk of half a koku in the old reckoning, perhaps thirty minutes by modern measure—she set out each morning as dawn broke.
Today, too, the sky hung gray. Clouds pressed low and heavy, and the damp wind rising from the Toki River brushed against her cheeks. Though summer's end was near, the mornings still held their coolness. Harune wore a thin haori over her plain kosode, cradling a basket of medicinal herbs in both hands.
"Forgive my intrusion."
As she passed beneath the temple's mountain gate, a voice leaked from the empty hall beside the main building. A groan, and beneath it, a low voice offering comfort. Harune hurried to open the door.
The interior of the empty hall had become a familiar sight by now. Seven patients lay stretched across straw bedding arranged on a three-mat wooden floor. A plague—similar to last year's Narumi epidemic, a sickness that ravaged the belly. Fever and diarrhea persisted, draining the body of its moisture until it withered from within. Left untended, it meant death. Harune knew this.
"Good morning, Lady Harune."
The greeting came from a young temple attendant named Tokutaro. Barely sixteen, perhaps, he had been persuaded by the head priest Kakumei to assist Harune. At first he had been uncertain, but now he volunteered readily to carry the boiled water.
Harune set down her basket and washed her hands. The water in the wooden bucket—heated thoroughly by fire the night before, then cooled—she scrubbed between her fingers with meticulous care. This was the first gate, the first barrier.
"Washing again, are we."
A hoarse voice rose from one of the beds. A farmer, perhaps fifty years old. The wrinkles etched into his face seemed somehow less pronounced than three days ago. A sign that the fever was breaking.
"Hand washing is the most important thing," Harune answered, placing her palm against his forehead. It was cool. Good, she thought.
"Can't believe a thing like this cures sickness."
The farmer grumbled, but his tone lacked the sharpness it had held at first. Harune still remembered the day the first patient had been brought to this isolation ward.
——The family members shouting, "Why should we trust the words of a woman we don't even know?" The merchants laughing, "What good is hand washing against a cursed plague?" The townspeople eyeing her with suspicion, "What's the castle's side-room candidate doing here?"
Harune had not argued back. She had simply remained silent and demonstrated it herself—washing her own hands, drinking the boiled water. "Please continue doing this. You'll understand why later," she had repeated.
*(I don't need them to believe. I only need to show them results.)*
She had made peace with that. Even in the modern world, people would not move until they saw with their own eyes. How much more so in this era, where talk of invisible bacteria would only fall on deaf ears.
"Tokutaro, could you prepare the decoction?"
"Yes!"
With an energetic reply, Tokutaro dashed away. Harune moved slowly through the ward, checking each patient in turn. She felt their foreheads for fever, watched to see if they could drink water, examined whether the straw bedding had grown damp.
One of the seven showed a markedly different complexion.
A girl of twelve or thirteen, lying on the innermost bed. Her name was Osato. When she had been brought in three days ago, her lips had been tinged with purple, and Harune had honestly not expected her to recover this far. Yet this morning, faint color had returned to her cheeks.
"...My belly doesn't hurt so much," Osato said quietly.
"Truly?"
"Yes. Much better than yesterday."
Harune took her hand. Her fingertips were slightly warm. The fever was breaking. This was certain.
Something spread slowly through her chest. Not quite relief—but the first true sensation, in this era, of her knowledge touching someone's life.
"I'm so glad."
She had spoken without realizing it. Her voice trembled slightly.
"Osato!"
The door to the empty hall burst open. The woman who rushed in was Osato's mother—the one who had wept outside yesterday, the one who had even resisted letting her daughter enter this place. Yet today she crossed the threshold without hesitation.
"It's true, her color—!"
The mother leaned close to examine her daughter's face, then looked at Harune. In her eyes dwelt something that had not been there three days before.
"Doing as you said... it worked."
The words were brief. The bow was shallow. But for Harune, it was enough.
Yet the scene was witnessed by more than just the patients in the empty hall.
Outside the door, a crowd had gathered without anyone quite noticing when. The wife of a nearby merchant house, a man who hauled cargo, a young couple with children. News traveled fast in the castle town. The story had spread by morning: "The side-room candidate at Jouenji Temple is healing the sick."
"If we do what that woman says, will we really get better?"
"My daughter's getting better..."
"Just from washing hands?"
Murmurs rippled through the crowd. Harune stepped outside.
"It is not hand washing alone," she said.
The people fell silent. Harune chose her words carefully.
"Using boiled water. Keeping the sick separated from the healthy. Only when all of these are done together does it work. If even one is missing, it means nothing. What matters is doing it every day, without fail."
"Will you teach us?"
The cargo hauler spoke. Harune nodded.
"I will. Here, today."
By the time the afternoon sun began to slant, nearly twenty people had gathered in the temple grounds. Harune demonstrated the proper way to wash hands to each one. Tokutaro carried the boiling cauldron, and smoke from the medicinal herbs that Isuke had sent drifted through the air.
She was exhausted. Her feet ached. Her voice had grown hoarse.
Yet watching the people before her wash their hands, strength seemed to well up from somewhere inexplicable.
Before she knew it, dusk had fallen.
As she left the temple gate and walked toward the castle, Harune turned back once. The roof of Jouenji Temple was dyed in the evening sun. The lantern hanging from the eaves of the main hall swayed gently in the breeze.
*(I'll continue. There's still so much to do.)*
She thought this and pressed forward with renewed purpose.
——But by the time she reached the castle, even that strength had reached its limit.
She passed through the great gate and stepped onto the stone path. Right foot, left foot. Each step felt heavy. A waiting maid rushed over and took her arm.
"Lady Harune, are you all right?"
"I'm fine. Just a little tired."
Even as she said it, her vision swam slightly. Supported by the maid, she made her way down the corridor of the eastern quarters. Light showed beyond the shoji screen.
*(That light...)*
Something was wrong. She always lit this room herself. The maids never entered to start the fire beforehand.
Harune slid open the shoji.
Someone was inside.
It was Nobukatsу.
He knelt before the standing lamp in the center of the room. Black hitatare. Hair cut short and dark. The usual expressionless face. Yet his eyes captured her the moment she entered, holding her gaze directly.
"...Lord Nobukatsu."
Harune instinctively stepped back. Her heart struck hard against her ribs. This man being here—it was a first.
"You're late," he said. His voice was low and devoid of emotion. Whether he was reproaching her or simply stating fact, Harune could not tell.
"My apologies. The work at Jouenji Temple ran longer than expected."
"Don't apologize."
He cut her off curtly. Harune entered the room and looked for a place to sit. Before she could settle, Nobukatsu spoke first.
"I was watching from the castle."
"...What?"
"Your movements. Leaving the castle this morning. Entering the temple. I saw the crowd gathering."
Harune found herself looking at his face. From the castle keep, the temple grounds would certainly be visible. He had been watching, she realized.
"[serious]I saw your work. The townspeople recovering. You did well."
Harune's thoughts stopped.
*You did well.*
This man—the one with a reputation for nothing but cruelty—had spoken words of praise.
Something pulsed in her chest. More than joy, surprise came first. She felt heat rise to her cheeks.
"I... thank you very much."
Her voice pitched higher. She tried to maintain composure, but failed.
Nobukatsu seemed about to say something. But there was a pause——
"[cold]However, do not overexert yourself."
His voice was quiet. It could have been an order, or concern, or both.
"If you collapse, it serves no purpose. I will have the plague measures continue. But rest tomorrow."
"But the patients still——"
"[serious]This Tokutaro can manage. Do only what cannot be done without you."
Harune fell silent.
*(This man understands that I am exhausted.)*
He truly had been watching from the castle. More than that—he knew who was helping at the temple. This was the kind of person he was. Not cruel, but moving with every detail calculated. He showed no emotion because it was more rational that way.
In that moment, her understanding of Nobukatsu shifted, ever so slightly.
"...Yes. I will rest tomorrow."
"See that you do."
Nobukatsu rose. The hem of his haori swayed. As he moved toward the door, he turned back once.
"[serious]The day after tomorrow, I will make an inspection tour of the castle town. You will accompany me."
With only that, he left. The shoji closed quietly.
Harune stood motionless for a long time.
*(Why me?)*
The question surfaced. To accompany him meant—that Nobukatsu would take her at his side when he ventured into the town himself. A side-room candidate. This woman of unknown origin.
The waiting maid returned softly to the room. As she adjusted the lamp's wick, she spoke in a low voice.
"It seems Lord Nobukatsu has taken an interest in you."
"Interest... or surveillance?"
The maid did not answer, only the faintest movement crossed her lips. It looked like a smile.
Harune approached the window. The lights of the castle town scattered below like stars. In the direction of Jouenji Temple, Osato would be sleeping by now. Tokutaro would be tending the decoction.
*(I might be able to live here.)*
When that thought came, something complex was born within her.
Her feelings toward Nobukatsu—she could not quite sort them out. Fear remained. That had not changed. But tonight, in the depths of those cold eyes, she had glimpsed something else.
It was frightening. But not only frightening.
Harune rested her hands on the window frame and gazed out at the night-shrouded castle town. One light, then another, went dark. People settling into sleep. An ordinary night in this era, in this place.
The day after tomorrow, she would walk this street beside Nobukatsu.
The thought of it left her chest unable to settle.