Xue Qinghe's body tensed.
A sound came from the corridor.
At first, it was far away. Heavy footsteps struck the concrete floor, one after another, with dull thuds: thump, thump, thump.
Each step came roughly two breaths apart, unhurried, as though someone were taking a stroll.
Along with the footsteps came a low rumbling sound.
It was not snoring, but more like the vibration a large beast forced from deep in its throat as it breathed, laden with foul air.
Xue Qinghe instinctively held his breath.
Beside him, Qin Chuan whispered, "Don't be nervous. The first wave is a ten-thousand-year one. It won't be too fierce. It picks rooms at random to smash, so it might not come here."
Xue Qinghe nodded, but his grip on the corner of the blanket did not loosen.
A small screen appeared on the wall of the room. Like a window, it showed the corridor outside.
Qin Chuan and Xue Qinghe looked at the screen at the same time.
On the screen, the corridor's fluorescent lights flickered.
Beneath the flickering lights, a figure appeared at the far end of the corridor.
It was tall. At least thirty feet. Its body was a translucent gray-black, as though formed from piled-up, congealed fog.
It had no distinct features. Where its head should have been, there were only two eerie green lights, like a pair of eyes.
Black mist constantly seeped from its body, trailing behind it like a long tail.
It walked slowly down the corridor.
It passed room 101 without stopping.
It passed room 102 without stopping.
It passed room 103.
Then it stopped.
Xue Qinghe stared at the screen, his fingers tightening around the blanket.
The Nightmare Demon stood before room 103. Its two green lights bobbed up and down, as though sizing it up. Then it raised a hand and slammed it heavily against the door.
Boom!
Even more than a dozen rooms away, Qin Chuan and Xue Qinghe felt the tremor.
On the image of room 103's door, the numbers changed. Its HP plunged straight from 100 to 40.
The second blow came.
Boom!
40 dropped to 0. The door shattered.
The Nightmare Demon stooped and squeezed into room 103.
There was no one inside.
An empty room.
The Nightmare Demon circled the room, let out a low roar, then backed out and continued wandering the corridor.
Qin Chuan breathed a sigh of relief.
"See? A ten-thousand-year Nightmare Demon can smash the starting door in two hits. That's why we have to upgrade it."
Watching the black figure roam across the screen, Xue Qinghe said tensely, "It can break a door with a hundred HP in two hits. Our door only has a hundred and fifty right now..."
"Right. So it's still not enough. We need to keep upgrading."
Qin Chuan checked their gold. Two-player mode doubled their income, giving them +4 per second. They had already saved up more than thirty coins.
He clicked "Upgrade door" twice.
The door's HP rose from 150 to 250.
Then he clicked "Upgrade turret" once.
The turret went from level 1 to level 2. Its barrel grew thicker, and a ring of blue, glowing markings appeared on it.
Qin Chuan kept saving gold and built a repair station as well. It looked like a small workbench fitted into a corner of the wall, with a hammer and several sheets of iron on top.
"The repair station repairs the door," Qin Chuan explained. "When the Nightmare Demon attacks, we can spend gold to repair it, restoring 50 HP each time. As long as our repairs keep pace with its attacks, the door won't break."
Xue Qinghe understood.
"What if its attacks outpace our repairs?"
"Then we have to rely on the turret to drive it away. The turret fires automatically every few breaths, and hitting the Nightmare Demon takes away its HP. Once it loses enough HP, it'll give up on this door and attack another room."
"Another room? But there are only two of us."
"Right. So once it makes a circuit and realizes ours is the only occupied room, it'll keep targeting us."
Xue Qinghe fell silent for a moment.
"Doesn't that make it really dangerous?"
Qin Chuan nodded. "That's why we have to upgrade the door and turret like our lives depend on it. The Nightmare Demon will grow stronger later, going from ten thousand years to twenty thousand, then thirty thousand. Its attack power will keep rising, so our defenses have to keep up."
As they spoke, the Nightmare Demon completed a long circuit of the corridor and finally reached the door to room 119.
Two eerie green lights shone through the gap beneath the door, swaying across the floor.
Xue Qinghe pressed his back firmly against the bed frame.
He could hear the breathing outside. So close. Only a door separated them.
Boom!
The Nightmare Demon struck its first blow.
The door's HP fell from 250 to 190.
Qin Chuan clicked the repair station once: 5 gold spent, door HP +50.
190 jumped back to 240.
Boom!
The second blow. 240 fell to 180.
Qin Chuan repaired it again: 180 jumped back to 230.
Boom! The third blow. 230 fell to 170.
Repair. 170 returned to 220.
The tug-of-war continued like that.
Xue Qinghe stared at the changing numbers on the door, his heart racing. Every time a crash rang out, he instinctively edged a little closer to Qin Chuan.
As he repaired the door, Qin Chuan said, "Don't panic. A ten-thousand-year Nightmare Demon deals 60 damage per hit, and I repair 50 HP, so we only lose 10 HP each time. As long as we have enough gold, we just need to hold out until it leaves."
Sure enough, after more than a dozen blows, the Nightmare Demon let out a roar, turned, and left.
Xue Qinghe exhaled.
"It's gone?"
"It's gone. But it'll come back."
Qin Chuan checked the panel. Their gold was still rising, already past a hundred coins. He upgraded the door twice in succession, bringing its HP to 350. He raised the turret to level 3.
"Once the turret reaches level 3, each shot takes 200 HP off the Nightmare Demon. A ten-thousand-year Nightmare Demon has 3,000 HP in total. When it comes to attack the door, the turret fires automatically. About fifteen shots will blast it away."
Listening to Qin Chuan's explanation, Xue Qinghe gradually relaxed.
Watching the numbers rise and fall on the panel, he suddenly began to find it interesting.
This felt completely different from fighting. A fight was a head-on clash, exchanging blow for blow. This game was about watching numbers, calculating timing, and allocating resources.
Two hours passed, and the Nightmare Demon came four times.
The first two times, it was at the ten-thousand-year level. They held out with the turret and door repairs.
On its third visit, the Clown Dwarf's voice rang out again: "Nightmare Demon evolution-twenty thousand years!"
Xue Qinghe's heart leaped into his throat.
The twenty-thousand-year Nightmare Demon was a size larger, its black mist thicker. Its two green lights had turned red.
The force of its blows had doubled. A single hit took 150 HP off the door.
Qin Chuan's fingers flew across the panel.
Repair the door. Upgrade. Repair the door. Upgrade.
Gold drained away in a torrent, and the door's HP jumped back and forth.
For one brief instant, the door's HP fell to 12.
12.
Only 12 HP stood between them and a broken door.
Qin Chuan's hand moved a fraction faster as he pressed the repair button. 12 jumped back to 62.
By then, Xue Qinghe had unconsciously leaned against Qin Chuan. His shoulder pressed firmly against Qin Chuan's body, and both his hands clung tightly to Qin Chuan's arm.
He had not noticed what he was doing. Or perhaps he had, but could not spare it any attention.
Crash after crash came from outside, each one shaking the bed.
The turret fired automatically, blue projectiles striking the Nightmare Demon one after another and blasting out clouds of black mist.
The Nightmare Demon roared and kept hammering the door.
The door's HP fell to 31 again.
Qin Chuan repaired it. 31 jumped back to 81.
The twenty-thousand-year Nightmare Demon struck again. 81 fell to 1.
The door held.
At that very instant, the repair cooldown finally ended, and 1 jumped to 51.
So close. Just that tiny sliver.
Xue Qinghe's fingers trembled around Qin Chuan's sleeve.
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