Mo Chen woke up to a familiar ceiling.
The fan above him hummed softly, stirring warm air that carried the faint smell of last night's dinner. The small crack near the corner of the room was still there, unchanged, just like it had been for years. When he sat up and looked around, everything felt… right.
Same room.
Same apartment.
Same city noises drifting in through the window.
His parents were still his parents. His life, at a glance, hadn't shifted even an inch.
And yet.
Something hovered in front of him.
It wasn't solid, but it wasn't a hallucination either. A translucent interface floated quietly in the air, as if it had always been there and Mo Chen had only just learned how to see it.
At its center was a single, empty text box.
Below it sat a line of text, neat and understated.
Causality Value: 10000
Mo Chen stared at it for a long moment.
"…Okay," he said quietly.
He waved a hand through it. His fingers passed straight through the image, meeting nothing but air. The interface didn't ripple or respond, but it also didn't disappear.
He got out of bed, washed his face, even pinched himself once just to be sure. The interface stayed with him the entire time, calmly hovering at the edge of his vision.
By the time two hours had passed, Mo Chen was sitting on the edge of his bed again, elbows on his knees, eyes fixed on the text box.
There were no menus.
No instructions.
No cheerful assistant popping up to explain the rules.
Just a box, and a number.
'So this is the whole thing?' he thought.
The name floated into his mind naturally, as if it had been pressed there along with the interface itself.
The Book of Causes and Effects.
Mo Chen exhaled slowly.
In reality, Mo Chen was still completely confused. The only clue was the causality value. He guessed that the text box allowed the user to input something extraordinary, consuming causality value to make it happen. As for what to input… of course, it had to be "cause" and "effect." Otherwise, why would it be called a causality system?
Talk was cheap. Time to test it.
Mo Chen focused on the text box and typed:
[Because Mo Chen drank a sip of water, he became a Great Luo Golden Immortal.]
Submit!
[Insufficient causality value. Please increase causality value.]
A mechanical voice echoed in Mo Chen's mind.
"Really!"
Just as he expected, cause and effect were the key. As long as the causality value was sufficient, the result could be achieved.
Becoming a Great Immortal was clearly impossible, so he tried something else.
[Because Mo Chen drank some water, he became a Taiyi Golden Immortal.]
Submit!
[Insufficient causality value. Please increase causality value.]
Again!
[Because Mo Chen drank some water, he became a Golden Immortal.]
[Insufficient causality value. Please increase causality value.]
[Because Mo Chen drank some water, he became a celestial being.]
[Insufficient causality value. Please increase causality value.]
[Because Mo Chen drank some water, he became an Earth Immortal.]
[Insufficient causality value. Please increase causality value.]
[Because Mo Chen drank some water, he became immortal.]
[Insufficient causality value. Please increase causality value.]
"Damn it!!!" Mo Chen cursed.
Was the system deliberately mocking him?
Fine. If godhood didn't work, he'd try superpowers.
Invisibility.Flight.Invulnerability.Teleportation.
Nothing worked.
The sky was still blue. The clouds were still white. Reality remained stubbornly normal.
"If the supernatural doesn't work, then let's try something natural."
Mo Chen changed tactics.
[Because Mo Chen drank a sip of water, he obtained a perfect physique.]
A perfect physique wasn't supernatural, right?
Submit.
[This setting requires 100 causality values. Confirm?]
The system response finally changed.
"Confirm."
Mo Chen rushed into the kitchen and eagerly took a sip of water.
"Cough—cough—cough!"
He choked from excitement.
Setting the glass down, Mo Chen touched his abdomen. The most obvious sign of a good physique was abdominal muscles.
A moment later, a wide smile spread across his face.
Eight-pack abs—clear, defined, and incredible to the touch.
He dashed to the bathroom, tore off his shirt, and stared into the mirror. Broad shoulders. Defined chest. Muscular arms. Two perfect V-lines.
This was undeniably a perfect physique.
He also noticed he had grown slightly taller.
"Huh? If body shape can be modified… can charm be modified too?"
His thoughts spiraled out of control.
He opened the system again.
[Because Mo Chen drank a sip of water, his charm reached the maximum value within the natural range.]
Submit.
[This setting requires 100 causality values. Confirm?]
"Confirm."
The moment he confirmed, his reflection changed. His facial structure sharpened, acne scars vanished, and his eyes became bright and captivating.
With this physique and appearance, Mo Chen was certain he could charm anyone.
But now wasn't the time for romance. Understanding the system came first.
He returned to the living room, brewed a pot of tea, sat on the sofa, and thought carefully.
Then he noticed something strange.
The causality value had changed—it was now 9802.
He had spent 100 values on physique and another 100 on charm. He should have 9800 remaining.
Where did the extra two values come from?
"Number of uses?"
Mo Chen rubbed his chin.
"That doesn't make sense. Spend 100 values and gain 1 back?"
Then a thought struck him.
Number of people affected?
After all, this was the Book of Cause and Effect.
After hours of thinking, this was the only explanation he could find.
"Let's test it."
Mo Chen filled a kettle with tap water and typed:
[Because Mo Chen tapped the kettle three times, the water inside turned into cola.]
Submit.
[This setting requires 1 causality value. Confirm?]
"…Only one?"
This shocked him.
He checked his remaining balance: 9801.
Perfectly accurate.
Mo Chen took a sip of the cola.
Cold. Fizzy. Delicious.
When he checked again, the causality value had risen to 9802, just as he predicted.
"Really…"
Now the method of increasing causality value was clear—it depended on how many people were affected.
Only one question remained.
Why did that setting only require 1 causality value?
With too few samples and no time to overthink, Mo Chen prepared his next experiment.