Siheyuan (courtyard house): My father, Li Yunlong!

"Section Chief Li, you've arrived. Based on yesterday's investigation and map analysis, I've formulated today's plan."

She hurried over, opened her notebook, and spoke quickly.

"We'll focus on three areas today. First, the equipment room and spare parts warehouse of the factory broadcasting station, where there are readily available lines and power supplies. Second, the old materials area in Warehouse No. 3, where many old and dilapidated machines are piled up, making it easy to hide things. Finally, the abandoned debugging workshop behind the technical department, a secluded location with complete power outlets. We'll split up for greater efficiency; I'll be in charge of..."

"Stop, stop, stop..."

Li Zhenhua was completely bewildered and quickly waved his hand to interrupt her.

"Captain Lin, your plan... it sounds like we'll be running ourselves ragged today. And what if we alert them by investigating so openly?"

Lin Taotao raised her eyebrows.

"Then what do you suggest we do? We only have seven days. If we don't hurry up and investigate, are we just going to wait for clues to come to us? If you're afraid of hard work, then don't do security work!"

Li Zhenhua looked around to make sure no one was nearby, then a mysterious smile appeared on his face as he lowered his voice.

"Who says I have to run on foot? I have a more efficient way."

"What method?"

Lin Taotao looked suspicious.

Li Zhenhua said no more and took out the heavy, clumsy, "old radio signal residue detector" from his canvas bag (actually taken from the system space).

Lin Taotao's gaze was instantly drawn to this strange "black brick," her eyes widening with confusion and curiosity.

"What...what is this thing?? A brick??"

Li Zhenhua weighed the heavy equipment in his hand, chuckled, and said in a pretentious tone.

"Bricks? Captain Lin, your eyesight is outdated. This is the latest high-tech reconnaissance equipment, specially used to find that thing."

He pointed in the direction of the factory area.

"high tech?"

Lin Taotao moved closer and carefully examined this strange thing she had never seen before. No matter how she looked at it, she thought it was unremarkable and even a bit rustic.

"Li Zhenhua, stop with the mystery! What is this? How do you use it?"

"Heavenly secrets must not be revealed."

Li Zhenhua remained mysterious, skillfully locating a hidden switch according to the system instructions, and gently pressed it.

A very faint buzzing sound came from inside the device, and a small LCD screen on the front lit up, emitting a pale green light. Some blurry grids and flickering dots began to appear on the screen. Li Zhenhua looked at the screen and silently recited something in his mind.

Whether you can solve the case depends on you!

Li Zhenhua stared intently at the flashing lights on the screen, while Lin Taotao held her breath and leaned closer, her face filled with disbelief.

On the screen, a simple grid map is clearly displayed with the location of the detector as the center, and seven or eight eye-catching red markers are distributed on it.

"This...this can really be found?"

Lin Taotao's voice was filled with surprise and doubt.

"High-tech, you know?"

Li Zhenhua was secretly delighted, but on the surface he pretended to be calm.

"Let's go back to the office and check the map!"

The two quickly returned to the intelligence department office.

When Lao Zhou, Lao Chen, and the others saw them return with serious expressions, carrying a "black brick" they had never seen before, they curiously gathered around them.

Li Zhenhua didn't bother to explain and directly asked Lao Zhou to unfold a detailed floor plan of the steel rolling mill, especially an attached diagram that marked the locations of all legal radio stations (such as the broadcasting station, communications department, and important workshop dispatch rooms).

"Map these points on the screen to correspond to their positions on the map!"

Li Zhenhua gave the order. The group immediately got to work, marking the relative positions and distances displayed by the detectors on the map one by one.

The results came out quickly.

Most of the red dots coincide with the locations of radio stations within the factory that are registered and have legal usage requirements.

This, in turn, proves the accuracy of the detector.

However, two red dots stand out conspicuously!

One is located in an area of ​​the administration building, but according to the registration, no radio station is installed there.

The other one was even stranger; it landed in an old office building that had been abandoned for many years on the edge of the factory area.

That building is said to have been left over from the Manchukuo period. It has been in disrepair for many years, and the power has been cut off for many years. It is usually completely ignored.

"These are the two!"

Li Zhenhua pointed heavily on the map with his finger.

"The administration building is in a sensitive location. The abandoned old building is in a secluded environment. Both are highly suspicious!"

Lin Taotao was completely captivated by the amazing equipment, and her professional instincts allowed her to quickly get into the zone.

"The administration building is crowded and noisy; operating during the day would easily alert them. The abandoned old building is in a more secluded location, making it better for hiding and easier to overlook. I suggest we scout the old building first!"

Li Zhenhua nodded in agreement.

"Just as I thought. Without further ado, let's go scout ahead. Lao Zhou, you two stay in the department, continue with your work as usual, and don't let anyone know."

To avoid attracting attention, Li Zhenhua and Lin Taotao did not leave the security office building through the main gate, but instead went around through the back gate, avoiding the main road, and followed the small path along the edge of the factory area, making their way towards the abandoned old building.

The closer you get to the old building, the more desolate the surrounding area becomes.

Weeds grew rampant, and discarded bricks, stones, and equipment parts were scattered all over the ground.

The old building has mottled walls and most of its windows are broken.

The two of them silently slowed their pace and cautiously observed their surroundings.

Li Zhenhua put the detector back into his bag, but his hand unconsciously went to his waist, where the pistol he was issued as the head of the security department was tucked.

Lin Taotao also looked solemn, and her right hand reached into her coat pocket to grip the gun handle.

Upon arriving at the entrance of the old building, a rusty iron gate was ajar, its lock long since broken.

Li Zhenhua and Lin Taotao exchanged a glance and gave each other a hand gesture.

Li Zhenhua gently pushed open the iron gate, and the jarring creaking sound was particularly clear in the silence.

The building was dimly lit, and the air was thick with the smell of mildew and dust.

They cautiously searched the first floor, but found nothing except broken tables and chairs and thick layers of dust.

"Let's go upstairs and take a look."

Li Zhenhua said in a low voice.

The stairs were made of wood, and they creaked as you stepped on them, making each step a nerve-wracking experience.

Upon reaching the second-floor corridor, the detector seemed to vibrate slightly, and the red dot on the screen became clearer.

They followed the signs and walked to a room at the end of the corridor.

The door was closed, but the dust on the doorknob seemed to have been touched recently.

Li Zhenhua gave Lin Taotao a wink, signaling her to be wary of what was behind her. He then leaned against the door, took a deep breath, and suddenly kicked the door lock!

The loud thud of the door being kicked echoed in the empty hallway. The wooden door swung open, slammed against the wall, and bounced back, kicking up a cloud of dust.

Li Zhenhua and Lin Taotao, one on the left and one on the right, cautiously entered the room with guns in hand.

This is an empty office, containing nothing but a few old desks and chairs and abandoned filing cabinets.