Searching for someone in northern Myanmar, and you call that earning tuition fees?

In the conference room of the Jiangnan City Criminal Investigation Detachment, a video recently intercepted from the dark web is playing on a loop.

The screen was pitch black, with only a distorted electronic voice echoing through the room. The sound was sharp and piercing, like scratching a blackboard with fingernails.

"Good evening, officers of Gangnam City."

"I heard you found an expert in optics? That's interesting. He can calculate my height and weight, and even spot my scoliosis. Looks like finally, someone with a brain has infiltrated that group of good-for-nothings who only know how to eat."

"but……"

The footage is shaking violently as the person filming tries to suppress their maniacal, twisted laughter.

"Do you really think that's all there is to me? The game has only just begun. I hope that optics expert survives to the end."

The video abruptly ended, and a blood-red 24-hour countdown slowly ticked in the center of the screen.

Jiang Nanyan's face turned ashen, and the ballpoint pen in her hand snapped in two with a "crack".

Ma Da gritted his teeth and slammed his fist on the table: "He's provoking us! This bastard is not only monitoring the police's movements, but also mocking us!"

"Has the technical department tracked the IP address?" Jiang Nanyan asked.

"It was another case of multiple broiler jumps, ultimately pinpointing a fishing boat in the Pacific Ocean," the technician said, sweating profusely. "And the video was released just ten minutes after our internal briefing ended!"

Is there a mole within the police department? Or rather, their network has been infiltrated to the point of being riddled with holes?

Jiang Nanyan took a deep breath, rubbed her throbbing temples, picked up her phone, and dialed Li Changfeng's number.

……

Security Department, Jiangnan University.

Li Changfeng, wearing an ill-fitting security guard uniform, stood on a chair, waving a baton and spitting as he spoke.

"Listen up, everyone! This is wartime! Level one alert!"

"Things aren't going well out there lately. From now on, any fly that flies into Jiangnan University, you'd better tell me its gender! Got it?!"

The security guards below looked at each other in bewilderment.

Security guard Lao Zhang pushed his hat brim up and said helplessly, "Lao Li, can't you just shut up for a second? I'm just a gatekeeper, and you're making this scene with flies around like this?"

"Old Zhang! Get your act together! Watch your step!" Li Changfeng glared.

Old Zhao glanced sideways, his gaze shifting downwards, before saying in a low voice, "Captain Li, put aside your awareness for now; your fly is undone."

Li Changfeng's old face instantly turned as red as a monkey's bottom. He turned around abruptly, frantically trying to tidy himself up, while still trying to convince himself, "Tactics...tactical ventilation! You guys don't know anything!"

Just then, Li Changfeng's cell phone rang in his pocket.

He took it out, grinned, and pressed the answer button.

"Advisor Li, where is student Su?" Jiang Nanyan's tired voice came through.

"Library, fourth floor, second seat by the window." Li Changfeng immediately lowered his voice, like a thief.

"He's currently engaged in a fierce battle with a CET-6 vocabulary book, and the situation is quite dire. I suggest you don't disturb him for the time being, so as not to affect the mental and physical health of our students."

"I have an urgent matter."

"Even if it's urgent, we have to wait until he gets past the obstacle of 'abandon'!" Li Changfeng said, heartbroken. "You know what? He's been stuck on that word for fifteen minutes! I'm almost ready to give up for him!"

From the other end of the phone came Jiang Nanyan's deep breaths, barely containing her anger: "...Advisor Li!"

"Sigh, fine, fine." Li Changfeng sighed, hung up the phone, dismissed the group of old foxes, and slipped into the library.

On the fourth floor, Su Ming was staring blankly at his vocabulary book, looking completely drained of energy.

"Abandon...abandon..." he muttered to himself, his finger unconsciously circling the pages. "A betrayal, an abandonment, a surrender...why can one word evoke so much distress?"

Li Changfeng cleared his throat, adopting the air of a life coach: "Su Ming, look, this word teaches us a profound lesson. Sometimes, when facing difficulties, like the CET-6 (College English Test Band 6), we need to learn..."

"Speak like a human being." Su Ming didn't even look up, turning a page of his book.

Li Changfeng's expression instantly fell apart, and he immediately became a sycophant: "That mother... Captain Jiang called and said that Shadow has updated his video again, and it's aimed at you."

Su Ming paused as he turned the pages of the book.

"Charge me?"

Li Changfeng handed over the phone. On the screen, a swaying black silhouette was accompanied by a jarring voice changer.

"A guy who knows optics has arrived? Interesting."

The video is short, but it's a blatant declaration of war.

Su Ming stared at the screen, rubbing his temples in frustration.

Provoking the police is suicidal, provoking me... is delaying my vocabulary memorization. This is worse than death.

Li Changfeng cursed, "That bastard is too arrogant! Su Ming, what do you think?"

Su Ming didn't say anything. He dragged the video progress bar back and played it again. Then he turned the phone volume up to the maximum, held it close to his ear, and closed his eyes.

Li Changfeng's head was throbbing: "Stop playing it! This sound is making my teeth ache. The technical department must have analyzed it; it's just a regular voice changer, and the background noise has been eliminated."

There is no absolute elimination.

Su Ming blocked out the shrill voice, and in his mind, a very low-frequency vibration was extracted.

hum... hum... hum...

It has a good rhythm.

Once every 45 seconds.

Su Ming suddenly opened his eyes.

He's at our school.

Li Changfeng was startled and instinctively reached for the baton at his waist: "What? That bastard is in our school? Which department? Which class? I'll go check his bank statement right now and get him expelled while I'm at it!"

Su Ming pointed to the brightly lit construction site outside the window and said, "There's a low-frequency noise in the background that loops every 45 seconds. That's the west campus teaching building that's under construction. The vibrations from the large pile drivers are transmitted through the earth's crust, causing physical resonance to the nearby recording equipment. No matter how cleanly he processes it, he can't remove this background noise."

Su Ming stood up and grabbed his schoolbag.

"He thought he was hiding in the shadows watching the show, and that I wouldn't be able to find him."

Li Changfeng looked completely bewildered: "Then what are you going to do now?"

Su Ming stuffed the "English Level 6 Vocabulary" into his bag, his eyes turning cold.

"Call Jiang's team, close the net, and collect the money."

"And teach him that there is no room for luck when it comes to physics."