"Clang—"

The hammer struck the wall, giving off a sharp metallic ring.

The recoil numbed Chen Yun’s arm; the hammer nearly flew out of his hand.

"Jesus." He hadn’t expected it to sound that loud and instinctively glanced around.

After a long moment of silence, he climbed onto the top of the wall to look around. Next door, Lin Wanwan’s window remained pitch black; the barren courtyard around them was utterly still.

Chen Yun let out a long breath. "Thank God…"

Back at the house, he inspected the spot he’d just hammered. The deep-gray surface showed not a scratch.

He looked down at the hammer in his hand—the handle was almost snapped in two.

"This thing’s tough." He shook his numb arm and couldn’t help admiring, "No wonder the system stuff’s always top quality."

"That’s enough for tonight. I’ll pick it up again tomorrow."

After making such a racket, he worried someone might have noticed. He didn’t want to risk continuing the reinforcement now.

He waved and retracted the hammer into his space, then pushed the door and went inside.

Nothing in the interior layout had really changed—tables, chairs, and the bed were in the same places—only the walls had turned that deep gray. Chen Yun walked to the window and tapped the glass gently; it vibrated faintly.

"The window glass didn’t get reinforced along with the wall. The furniture didn’t either," he murmured. "So the last two reinforcements only affected the house’s structural framework."

"Looks like I’ll have to reinforce every windowpane too."

He put his hand on the glass, pulled up the system panel, and selected Reinforce.

[Reinforce target: Window?]

[Cost: 40 survival points.]

"No materials required? Direct reinforcement costs 40 points—still acceptable." He thought for a beat and hit Yes.

[Confirmed. Consume 40 survival points.]

[Reinforcing...]

[Reinforcement successful!]

His vision blurred for a second. The window changed.

The old wooden frame vanished, replaced by a matte black-and-gold metal frame. It fit the wall so snugly it looked fused to it. The dust-caked glass turned thick and brilliant; hammer it as hard as you wanted, it wouldn’t budge.

Chen Yun tried opening one of the panes—smooth and soundless. When he closed it there was only a soft click; it sealed perfectly.

There were eight windows on the exterior walls. He repeated the process and reinforced them all, spending 320 points in total. The interior partition windows were left alone for now to save points.

He inspected the new windows and nodded, satisfied.

He glanced at the clock on the wall—already past one in the morning.

"Time to call it." He stretched, rinsed quickly, and went to the bedroom.

Lying on the old wooden bed, listening to the faint summer cicadas outside, he drifted off and slept deeply the whole night through.

At dawn, Chen Yun woke just as the sky was lightening. He dressed, washed up, and went to the kitchen to make something to eat.

Even the old earthen stove had changed. The brick hearth that had been stacked with mortar was now the same deep gray as the walls. The structure was the same—just the material finish had been altered.

"The stove’s technically part of the house’s structure," he said, surprised but understanding. The stove had been built with the same bricks and cement when the house was made, so it made sense the reinforcement would include it.

"Nice bonus," he admitted.

He didn’t use the stove—there was an induction cooker—so he boiled some noodles and ate quickly. Finished, he opened the door and stepped into the yard.

The morning air carried dew and the clean scent of grass. He turned to regard the reinforced wall. Last night it had been too dark to see details; in the clear daylight every seam and texture showed plainly.

The rising sun hit the deep gray and threw back a faint metallic sheen.

"No wonder it rang like metal when I hit it—there must be metal elements on the surface," Chen Yun said, a little shocked. "I couldn’t tell inside the house last night."

Composed again, he climbed onto the wall to look around. After making sure no one was watching their yard, he went to the center of the courtyard and produced some bricks from his space.

He headed straight for the corner covered by a stone slab—the cellar.

This was the underground portion of his old-house renovation plan. He placed his hand on the cellar lid, summoned the system screen, and thought the activation phrase: targeted reinforcement, expand space.

[Reinforce current cellar?]

[Direction: Space expansion.]

[Required points: 1,500. Current balance insufficient.]

"So you can expand it directly, but it needs points," he murmured. "No mention of using materials as offsets." He remembered earlier when expanding the oil drum had used empty drums as the material cost. It made him think: maybe to expand a space, you can trade in material volumes—i.e., build hollow blocks to count as expendable volume.

If that logic held, he could make hollow cement-brick cubes and use those to discount points needed for cellar expansion.

He dragged over two bags of cement and a pile of sand, grabbed a shovel from his space, and slit open a bag. Mixing cement and sand at a one-to-five ratio, he added water and stirred hard.

Soon the mortar was ready. He grabbed a stack of red bricks and began building. The bricks weren’t soaked first, but for now they’d hold; they only needed to be a consumable.

He spread mortar and set the first brick, then the next, laying them in staggered rows. Near the top he slipped in a few thin rebar pieces as a makeshift lintel, then capped it with another layer of brick.

Before long a hollow cube roughly one meter on a side sat in the yard, mortar still dark and damp in the joints.

"Ah…" Chen Yun straightened and took a breath. He walked to the cellar slab and pressed his hand to it.

[Apply basic reinforcement to current cellar?]

[Detected hollow brick cube. Consume hollow brick cube to apply targeted reinforcement?]

[Direction: Expansion.]

[Required points: 1,450.]

"It works." He brightened. "One 1-cubic-meter hollow brick cube discounts 50 points."

"Let’s see what other sizes discount."

He went back to laying bricks. Before long he’d built a two-cubic-meter rectangular hollow block.

[Required points: 1,420.]

"A two-cubic discount is 80 points," he calculated. "Looks like the single-cubic unit gives the best ratio."

He wiped sweat from his brow and turned to make another cube when—

"Knock, knock—"

A series of knocks sounded at the courtyard gate.