The first thing I noticed when I woke up was the dampness. It wasn't just in the air; it had settled into my bones, a deep, aching cold that made my joints feel like rusty hinges.

  I opened my eyes. The ceiling was a patchwork of dripping, moss-covered brick arches. We were deep underground in the "Sump"—Rax's emergency bolt-hole in the old sewer maintenance tunnels.

  The second thing I noticed was the smell. It was a mix of stagnant water, machine oil, and something cooking that smelled suspiciously like wet socks.

  I groaned and sat up on the canvas cot. My body protested every inch of movement. My arms, which had wrestled with the hydraulic levers for twenty minutes straight, felt like lead weights.

  "You look like a corpse that walked out of a grave," a gravelly voice noted.

  Rax was sitting on a crate near a small camp stove, stirring a bubbling pot. The orange light of the burner cast long, dancing shadows against the curved walls. The silent, cooling hulk of the Centurion loomed in the darkness behind him like a sleeping dragon.

  "I feel like one," I rasped. My throat was raw from the smoke.

  I swung my legs off the cot and looked to my left. Amelia was still asleep on the other cot. She was buried under a pile of moth-eaten wool blankets Rax had scavenged. Her face was pale, almost translucent in the dim light, and dark circles bruised the skin under her eyes. She looked small. Fragile.

  I felt a sharp pang of guilt in my chest, heavier than the ache in my muscles. I walked over to her quietly. She was breathing, shallow but steady. I reached out and tucked the edge of the rough blanket around her shoulder. She didn't stir.

  "She burned hot yesterday," Rax said quietly, handing me a tin mug. "I've seen battle-mages burn out their cores before. It takes weeks to recover. Sometimes they never do."

  I took the mug. The liquid inside was a murky green. "What is this?"

  "Moss soup," Rax grunted. "Rich in iron. Tastes like dirt. Drink it."

  I took a sip. He was right; it tasted like warm mud seasoned with rust. But the warmth spread through my chest, chasing away the sewer chill.

  "I treated her like a component," I said, staring into the green liquid. "I needed power, so I just... turned up the dial. I didn't think about the load limit."

  Rax took a swig from his own mug. "You're an engineer, kid. You look at problems and you see levers and gears. But she's not a gearbox. You strip a gear, you replace it. You strip a person..." He tapped the metal plate on the side of his own head. "You lose pieces you can't buy back."

  I looked at Amelia again. I remembered the blood running from her nose, the way her hands had shaken uncontrollably as she poured her life force into the distributor. "It won't happen again," I said, my grip tightening on the mug. "I'm going to fix it."

  "Good," Rax stood up. "Because if you kill her, I'm out of a job. Now, drink up. We have work to do."

  An hour later, Amelia stirred. I was sitting on the floor, sketching on the back of a ration wrapper, when I heard the rustle of blankets.

  "Julian?" Her voice was weak, barely a whisper.

  I dropped the charcoal and was at her side in a second. "I'm here."

  She tried to push herself up, but her arms trembled and gave out. She fell back onto the pillow, frustration flashing across her face. "I can't... I feel so empty," she whispered, staring at her hands. "My mana... it's just a trickle."

  "Don't try to channel," I said quickly, pouring water from a canteen into a clean cup. "You hit zero. You need to recharge naturally."

  She took the water, her hands shaking so much I had to help her hold the cup. "I'm sorry," she said after drinking. "I held us back. If I was stronger... if I could have kept the pressure up..."

  "Stop," I cut her off, perhaps a little too sharply. I softened my tone. "Amelia, look at me. You didn't fail. The machine failed you."

  I picked up the sketch I had been working on. It was a diagram of two fan-like wheels facing each other inside a donut-shaped casing.

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  "The V8 engine is a beast," I explained, holding the drawing so she could see it without lifting her head. "It spins at three thousand revolutions per minute. It's violent. And the legs... they are heavy and slow. Connecting them directly was like trying to stop a spinning buzzsaw with your bare hands. The shockwave traveled right back up the line and hit you."

  Amelia blinked, trying to focus on the drawing. "So... we need better gears?"

  "No. Gears are solid. They break. We need something liquid." I pointed to the space between the two fans in the drawing. "This is a Torque Converter. Imagine these two fans. They don't touch. The space between them is filled with oil."

  I moved my hands to demonstrate. "The engine spins the first fan. It throws oil at the second fan. The oil pushes the second fan, which moves the legs. If the legs get stuck, or if the engine jerks... the oil just slips. It absorbs the shock."

  I looked her in the eyes. "It's a cushion. A buffer. It means the engine can scream all it wants, but the power that reaches you—and the legs—will be smooth. Soft."

  Amelia looked at the drawing, then up at me. A faint smile touched her lips. "That sounds... expensive."

  "Cheaper than you having a stroke," I said, forcing a smile. "Rest. Rax and I are going shopping."

  The "shopping trip" didn't require leaving the Sump. Rax led me to the far end of the facility, where massive, rusted iron pipes disappeared into the dark water. "These are the old centrifugal storm pumps," Rax said, kicking a housing the size of a small car. "Haven't run in fifty years."

  "Perfect," I said, running my hand over the rusted casing. "We don't need the motors. We need the impellers."

  We spent the next four hours in a shower of sparks. Rax used a heavy oxy-acetylene torch (scavenged from the mines) to cut through the inch-thick cast iron casings. I used a pry bar to crack the seals.

  When we finally pulled the impeller out, it was a thing of heavy, industrial beauty. It was a heavy iron wheel with curved vanes, designed to throw water with massive force. We needed two.

  By the time we hauled them back to the Centurion, Amelia was sitting up. She had wrapped the blanket around herself like a shawl and was watching us with interest.

  "Can I help?" she asked.

  "No magic," I warned.

  "I can blow away the smoke," she offered. "Gently."

  I nodded. "Deal."

  The fabrication process was a delicate dance of brute force and precision. I had to weld the two impellers into a sealed housing, fill it with hydraulic fluid, and mount it between the engine's output shaft and the main hydraulic pump.

  "Hold this steady," I told Rax as I aligned the heavy iron housing.

  Rax grunted, holding the hundred-pound part still with his mechanical arm. I lowered my welding mask. ZZZRT! Blue light flared, illuminating the damp walls of the Sump.

  As I welded, a gentle, cool breeze circled around my head, whisking away the acrid fumes of burning metal and flux. I looked over. Amelia was sitting on the cot, one finger raised, directing a tiny current of air with a look of intense concentration. It wasn't a grand storm. It was a caress.

  It was peaceful. For the first time since I arrived in this world, I wasn't running for my life or building a weapon of mass destruction. I was just fixing a car in a garage with a friend.

  "Done," I said hours later, flipping up my mask. The Torque Converter sat bolted to the back of the V8 engine. It looked like a giant, bulbous iron donut. It wasn't pretty, but it was sealed tight.

  "Will it work?" Rax asked, wiping grease from his good eye.

  "Only one way to find out," I said.

  I climbed into the pilot's seat. It felt different now. Less like a torture device. "Clear the area!" I shouted.

  I looked at Amelia. "Ready for a test?" She nodded, though she looked nervous. She placed her hand on the distributor.

  "Just a little," I said softly. "Don't push. Just let it flow."

  She closed her eyes. The copper coils began to glow with a soft, warm orange light. Chug... chug... purr.

  The V8 caught. But this time, it was different. Before, the engine would have bucked and stalled as it fought against the inertia of the stationary hydraulic pump. Now, the engine spun freely. The oil inside the torque converter was slipping, allowing the engine to build up speed without load.

  "Idle is stable," I announced, watching the RPM gauge. "Engaging drive."

  I pushed the left leg lever forward. In the past, this would have resulted in a violent CLANG and a jerk that rattled your teeth.

  Instead, I heard a deep, rushing sound—the sound of fluid churning inside the converter. The power transfer wasn't instant. It built up. Like a wave rising.

  Whirrrrrr...

  The massive steel leg of the Centurion didn't jerk. It didn't shudder. It simply... floated. It rose smoothly from the ground, the motion fluid and controlled. I eased the lever back, and the foot lowered gently, touching the concrete with a soft thud rather than a crash.

  "It works," I breathed, feeling the difference in the levers. The vibration was gone. The violence was gone. It felt like I was driving through water.

  I looked back at Amelia. She was staring at her hand, eyes wide. "I didn't feel it," she whispered. "No kickback. No drain. It felt... soft. Like pushing cotton."

  I climbed down from the cockpit and wiped my hands on a rag. Rax walked up and kicked the new housing. "It doesn't scream anymore."

  "No," I smiled, looking at the silent, idling giant. "It doesn't."

  I walked over to Amelia. She looked exhausted but relieved. The color was returning to her cheeks. "We have a transmission," I said. "And you have a safety buffer."

  "It's nice," she said, leaning back against the cool stone wall. "It feels less like a monster now."

  "It's still a monster," I said, looking at the ten-foot-tall machine of war. "But now, it's our monster. And it listens."

  I sat down on the crate next to her, picking up my cold soup. "Eat," I said. "Tomorrow, we weld the armor. But tonight, we just let it idle."

  For the first time in days, the constant knot of anxiety in my stomach loosened. We were deep underground, hunted by the city, eating moss soup, and smelling of sewer water. But the engine was purring. And Amelia was safe. It was enough.