The Bluebird landed on the roof of the train; the metal deck gave a dull shudder.

He vaulted neatly into the carriage, and the moment the Internal-Combustion Engine wreckage touched the floor a few ghost-blue sparks spat out.

“You're hurt.” Bai Cheng spotted a ragged tear at the base of [N O V E L I G H T] his left wing; among the scorched feathers a faint blood-trail showed.

The Bluebird flicked his wing carelessly. “Just a scratch.”

Bai Cheng frowned; she hadn't expected those black mists to wound a King-level like Bluebird.

According to Purple Iris, Bluebird was no longer an ordinary King-level.

Bai Cheng called it a Second-stage King-level.

“Looks like these black mists really aren't simple.” Bai Cheng looked at Bluebird and said gravely, “No more risks from now on.”

Bluebird offered no argument; he simply bowed his head. “Understood.”

Seeing this, Lvdou stepped forward to treat him, but a single Guardian Level healer could not fully mend a King-level wound.

Still, her life energy carried a purifying effect; after treatment only surface injuries remained—time would do the rest.

Yu Nian, standing to one side, quietly exhaled when she saw Bluebird return safely.

As for such minor wounds, she felt they hardly mattered.

What she cared about now was the Internal-Combustion Engine wreckage before them.

After sensing it for a moment her brows stayed knit. “Xiao Cheng, with my talent I can restore it—but it'll take hours...”

She turned to Bluebird. “How long can you hold off those black mists?”

That would decide whether they stayed put or kept going.

“Miss, the mist's corrosion doesn't work on living things, and once the lightning element is drained they're pathetically weak.”

Bluebird's words were a shot of reassurance; everyone finally relaxed.

So there was no need to rush.

Lan Xiaoyu powered up her gear and began scrubbing parts; Yu Nian devoted herself to rebuilding the engine.

Bluebird kept his Domain up to hold the enemy at bay, while the others busied themselves with their own tasks.

Everything proceeded as usual, and soon deep night arrived.

As Lan Xiaoyu cleaned more and more parts, the pieces turned silvery-white and gleamed.

Whether because the train's overall grease was diminishing or Silent Night was about to fade, the black mist's erosion grew thinner with every passing hour.

Bluebird, now under no pressure, even acted as courier between Bai Cheng and Liu San's trains, tossing over equipment they no longer needed.

Time marched on until dawn; Silent Night receded and the churning black clouds settled back into tranquil white—peaceful and calm.

Exhausted, Yu Nian finally restored the Internal-Combustion Engine after a whole night's effort.

Meanwhile the scrubbing of parts had never stopped, so every material for the upgrade was ready at almost the same instant.

“Phew, done!” Yu Nian plopped onto the floor, wiped the sweat from her forehead, and breathed easy.

She turned to Lan Xiaoyu, still busy nearby. “Xiaoyu, how many cleaned parts do we have now?”

Lan Xiaoyu counted in silence. “Over five hundred—more than enough to upgrade the train.”

“Great!” Yu Nian instantly brightened.

She jumped up and sprinted toward the bedroom, shouting, “Xiao Cheng, wake up—our train can level up!”

Bai Cheng woke groggily; the moment she heard Yu Nian she snapped fully alert.

“So fast? Wonderful!”

Leng Ningxue was roused as well; in pajamas and slippers she hurried with Bai Cheng to the bedroom screen.

The three squeezed together, eager to see what qualitative changes the upgrade would bring.

“Quick, quick!”

Bai Cheng opened the upgrade panel; seeing every material checked, she didn't hesitate—she tapped Advance.

In the next instant a flash of white light enveloped the entire train.

The upgrade finished in a heartbeat, and the first thing the trio noticed was the interior makeover.

Level wooden floors, leather trim, double-layer pressure-proof windows, constant-temperature system, air-purification—everything included.

There were also small touches: curtains, adjustable window opacity, and the once-simple bunk beds now looked luxurious.

And that was only the bedroom.

When Bai Cheng's trio inspected the other rooms, the changes were equally stunning.

The kitchen, for instance, now had tiled walls, a range hood, cutting boards—everything.

The planting and livestock areas were rationally apportioned, as though the train already knew how they'd divided each car's duties.

Yet what surprised Bai Cheng most wasn't that.

Before, refitting the train had required décor blueprints; after advancing, the train automatically came with furniture.

The changes were truly unexpected.

“This is like jumping from the eighties straight to the twenty-first century!” Yu Nian exclaimed, eyes wide.

In the driver's cab the transformation was equally dramatic.

The steam pipes and boiler at the head were replaced by silver-white Internal-Combustion Engine assemblies; precision parts reflected the morning light like mirrors.

The engine took up only sixty percent of the old boiler's space yet doubled output, humming softly at startup.

The cab also gained a monitoring system for real-time perimeter scans, and the detection console now featured holographic projection—everything turning smarter by the minute.

That was merely the interior; the exterior had changed astonishingly too.

The nose was sheathed in composite-metal armor, sleek and silver.

Hydraulic dampers at the couplings had eliminated the clatter of the steam age.

“Wait—we've been gawking at the upgrades,” Bai Cheng suddenly said. “Where do we get fuel?”

With the old steam train fuel had been everywhere; they'd never worried.

But now that they'd upgraded to an Internal-Combustion Engine train, things looked worse.

Not only was fuel harder to obtain, they'd also lost the most important fuel supply on the whole channel.

“Hiss—” Leng Ningxue sucked in a breath. “Did we upgrade too soon?”

“Young ladies, don't worry,” Lan Xiaoyu said calmly.

She fished out a canister of black liquid from the cleaning rig and explained:

“This grease contains enormous energy; I believe it's the main fuel for the Internal-Combustion Engine.”

The three finally breathed easy.

Bai Cheng stepped forward for a closer look.