My head was pounding with the kind of rhythm that makes you want to crawl into a dark hole and stay there for a month. The fever from the last few days had finally broken, leaving me soaked in a cold, sticky sweat that made my clothes feel like they were made of wet lead. I sat on a stump near the river, watching the water wheel. It was still turning, but the sound had changed. There was a slight squeak in the axle, a tiny friction point that told me the wood was wearing down faster than I liked. In my old world, I would have just sprayed some industrial lubricant on it and forgotten about it. Here, I had to figure out how to render pig fat into something that wouldn't turn into a sticky mess in the heat.
Everything was a trade-off. To get the pig fat, I had to talk to the farmers. To talk to the farmers, I had to explain why I was taking their food to feed a piece of wood. They didn't see an engine; they saw a hungry monster that ate their trees and now wanted their bacon.
Lao walked up, dropping a heavy bundle of leather hides at my feet. The smell was enough to make a dead man gag. It was raw, poorly cured, and still had bits of salt and hair clinging to the edges.
That is the last of it, Lao said. He wiped his face with a rag that was just as dirty as the leather. The villagers are starting to hide their goats, Lu. They think you are going to make a wheel out of those, too.
I looked at the leather. It was thin, but if I layered it with a coating of pine resin and stitched it tight, it might hold the pressure. I needed it to hold enough force to push a stream of water through an iron nozzle. I wasn't building a garden hose. I was building a defensive weapon.
I don't care if they hide their goats, I said, my voice sounding like I'd been eating glass. I need the resin. Tell the children to go to the pine grove and start tapping the trees. I'll give them a copper coin for every bucket they bring back.
Lao frowned. We don't have many copper coins left, Lu. You spent most of them on the charcoal.
Then tell them I will owe them, I snapped. Or tell them that if the Governor's men come back, they won't have goats or copper coins to worry about because their houses will be ash.
Lao sighed and walked away, his heavy boots making deep sucking sounds in the mud. He was tired. I was tired. The whole village was vibrating with a kind of nervous energy that felt like a bridge right before the cables snap.
I spent the rest of the morning working on the lathe. It was a crude thing, powered by a belt connected to the main water wheel shaft. I had used a sharpened piece of our first iron batch as the cutting tool. My goal was to turn a solid cylinder of iron into a hollow nozzle with a tapering bore. In 2025, a CNC machine would have done this in six minutes. For me, it was a battle of millimeters. One wrong move, one slip of the hand, and the tool would catch and shatter.
The metal screamed as the lathe turned. High-pitched, metallic shrieks that set my teeth on edge. Tiny curls of iron fell into the mud, glowing red for a split second before dying out. I was focused so hard that I didn't notice someone standing behind me until a shadow fell across the workbench.
I jumped, my hand twitching. The cutting tool bit too deep, and a shower of sparks flew into my face.
Dammit! I yelled, pulling the lever to stop the belt. I turned around, ready to tear into whoever had snuck up on me.
It was a girl. She couldn't have been more than nineteen. She was wearing a simple blue tunic, patched at the elbows, and her hair was tied back with a bit of twine. She was holding a small basket of steamed buns, and she looked terrified.
I am sorry, Master, she whispered, bowing so low the basket almost hit the dirt. I was sent to bring you food. My name is Han.
I took a deep breath, trying to slow my heart rate. The adrenaline was making my hands shake. I looked at the nozzle. I had gouged a deep scar into the side of the metal. It wasn't ruined, but it was ugly.
Just leave it on the bench, I said, turning back to the machine.
She didn't leave. She stood there, her eyes darting around the workshop. She wasn't looking at me; she was looking at the drawings on the silk. She was looking at the way the gears moved. Most of the villagers looked at my machines with a kind of dull fear, like they were staring at an eclipse. But her eyes were different. She was tracking the movements. She was looking for the logic.
Is that how the water moves? she asked, pointing to the valve assembly I had sketched out.
I stopped what I was doing and looked at her. Yeah. The pressure builds in the chamber, and the valve regulates the flow. Why?
She tilted her head. My father was a carpenter. He used to say that water is like a stubborn horse. If you try to pull it, it digs in its heels. But if you give it a path, it will run until it drops.
That's a good way of putting it, I said, surprised.
I took one of the buns from her basket. It was warm and soft, and for a moment, I forgot about the iron and the mud. I realized I hadn't talked to anyone besides Lao or the elders in weeks. I'd forgotten that there were people in this village who weren't just labor units.
She stayed for a few minutes, asking questions that were surprisingly smart. She wanted to know how the belt didn't slip when it got wet. She wanted to know why the iron didn't break when it was red hot. I found myself explaining the basics of friction and tempering, things I hadn't thought about in years. It felt good to be a teacher instead of a taskmaster.
But after she left, a cold feeling settled in my stomach.
Lao! I shouted.
He came jogging over from the riverbank, looking worried. What's wrong? Did the axle snap?
Who is the girl? Han? I asked.
Lao relaxed a bit. Oh, she's the carpenter's daughter. Her father died in the last flood. She helps her mother with the weaving. Why? Did she do something?
She was asking questions, I said. Specific questions. About the valves. About the belt.
Lao shrugged. She's a curious kid. Always has been. Used to sit in her dad's shop and watch him work for hours.
Maybe, I said. But Feng said he'd be back. And men like Feng don't just wait. They send someone ahead to see what they're up against.
Lao's face went hard. You think she's a spy? She's just a girl, Lu.
The most effective spies are the ones you don't suspect, I said. I was an architect in a high-stakes world, Lao. I've seen people sell out multi-billion dollar projects for a better office view. If she's looking at my blueprints, she's looking at our defense.
I spent the rest of the day in a state of paranoia. Every time I saw a movement in the trees or heard a whisper behind a hut, I felt like someone was taking notes. I moved the silk drawings into my shack and started locking the door with a heavy wooden bar.
I spent the evening stitching the leather hoses. It was agonizing work. I had to use an awl to punch holes through three layers of thick hide, then pull a waxed cord through. My fingers were raw and bleeding by the time the sun went down. I coated the inside with the pine resin the children had brought, the sticky stuff smelling like a forest on fire.
By the middle of the night, I had ten feet of hose. It was stiff, ugly, and smelled like death, but it was airtight. I connected it to the iron nozzle and the pressure tank I'd built from the old cauldron.
The next morning, we tested it.
I had the men position the tank near the water wheel. I connected the drive shaft to the pump piston I'd cast yesterday. As the wheel turned, the piston began to move back and forth, sucking water from the river and forcing it into the tank.
I could hear the air whistling as it was compressed. The leather hose began to swell, the resin-soaked seams groaning under the strain.
Lu, it's going to pop! Lao shouted, backing away.
I stood at the end of the hose, holding the iron nozzle. My heart was racing. If the leather failed, I was going to get a face full of high-pressure water and raw hide. But I had to know.
I turned the valve.
A jet of water shot out of the nozzle with a sound like a whip cracking. It wasn't a splash; it was a solid white pillar of force. It hit a wooden fence twenty yards away and didn't just wet it—it shattered the planks. The recoil was so strong it almost knocked me off my feet. I had to lean my entire weight forward just to keep the nozzle pointed straight.
The villagers who were watching let out a collective scream. Some of them fell to their knees. To them, I had just turned the river into a spear.
I shut the valve. The hose went limp, and the silence that followed was heavy.
It works, I breathed, my arms shaking from the effort.
It's terrifying, Lao said, walking up to the shattered fence. He touched the splinters of wood. If that hit a man...
It would break his ribs and take him off his horse, I said.
I looked back at the village. Near the corner of the granary, I saw a flash of blue fabric. It was Han. She was watching us. She didn't look terrified like the others. She looked like she was memorizing the distance.
I handed the nozzle to Lao. Keep an eye on the pump. If the pressure builds too high and I'm not here, open the release valve. Don't let it sit full.
Where are you going? he asked.
To have a talk with our carpenter's daughter, I said.
I followed her back toward the weaving huts. She was fast, moving through the mud with a grace I didn't have. I finally caught up to her near the edge of the woods.
Han! I called out.
She stopped and turned around. She looked calm. Too calm.
Yes, Master?
That was a lot of questions you had yesterday, I said, walking closer. I noticed my hand was resting on the small knife I kept at my belt. I wasn't going to use it, but the weight of it was a comfort. You seem very interested in how things work for someone who just weaves silk.
She looked at me, her eyes steady. I am interested because I want to know if we are safe. My father died because the levee was weak. If your machines are strong, then maybe my mother won't drown this year.
It's a good story, I said. But the way you were looking at the gears... that wasn't a girl looking for safety. That was an engineer looking for a weakness.
She smiled then. It wasn't a shy girl's smile. It was sharp. You are very observant for a prince, she said. But you are wrong about one thing. I am not looking for a weakness to help the Governor. I am looking for a weakness because I want to know if you are actually as smart as you think you are.
And? I asked.
She stepped closer, her voice dropping to a whisper. Your pump is leaking at the secondary seal. The leather you used is too soft. In two days, the water will eat through the resin, and the hose will burst. You need to use cowhide, and you need to tan it with oak bark for twice as long.
I stood there, stunned. My 2025 pride took a direct hit. I looked back at the pump. I hadn't noticed the leak. But now that she mentioned it, I could see a tiny mist of spray near the base of the piston.
Who are you? I asked.
I am exactly who Lao said I am, she replied. But my father didn't just build chairs. He built the siege engines for the southern border. He taught me everything he knew because he didn't have a son. And if you want that wheel to survive the Governor's men, you're going to need more than just one hose.
She turned and started walking away.
Wait! I called out.
She stopped but didn't turn back.
If you knew it was leaking, why didn't you tell me yesterday?
Because yesterday, I didn't know if I could trust you, she said. I wanted to see if you would build a toy or a tool.
I watched her disappear into the shadows of the huts. My head was spinning. I had been looking for a spy, and I found a lead engineer. In 2025, I would have hired her on the spot. Here, I didn't know if she was a gift or another complication.
I walked back to the water wheel. Lao was standing there, looking at the leaking pump.
She was right, Lu, he said, pointing to the mist. It's getting worse.
I sat down on my stump and rubbed my face with my hands. I felt like a fool. I had been so worried about the "Old World" people and their superstitions that I hadn't realized there were people here who actually understood the craft.
Fix it, I said. Get the cowhide. And find some oak bark.
Lao looked at me. What did she say to you?
She told me I was doing it wrong, I said, a small, tired smile tugging at my lips.
I looked at the water wheel. It was still turning, the steady thump-thump-thump keeping time with the rising river. I had a water cannon, a leaking pump, and a girl who knew more about siege engines than I did.
The blueprint was getting bigger again. It was no longer just about survival. It was about building an industry.
We're going to need a bigger workshop, I said.
Lao laughed. We're going to need a miracle, Lu.
Miracles are just engineering we haven't finished yet, I replied.
I picked up my charcoal and started to redraw the seal assembly. I didn't lock the door that night. I figured if anyone was going to steal my ideas, they might as well be the ones who knew how to make them better.
The rain started to fall again, but I didn't mind. I had a nozzle, I had a wheel, and for the first time in this world, I felt like I had a peer.
But as I lay down to sleep, I thought about the Governor. If a carpenter's daughter could see the flaws in my work, what would an army see? I had to be better. I had to be perfect.
I fell asleep dreaming of oak bark and high-pressure valves.