Bai Bing moved the mouse so that the point of view rapidly descended from space to hover above the city, which seamlessly filled the screen. He panned around, searching carefully, and quickly found the No. 2 Detention Center at the city outskirts, then the three-story building they were in. The point of view entered the building, gliding along the empty hallway on the second floor. The two plainclothes detectives sitting on the bench outside appeared onscreen, Chenbing lighting a cigarette. At last, the screen displayed the door of the office they were in.

“Right now, the simulation only lags behind reality as it happens by 0.1 seconds. Let’s go back a few minutes.” Bai Bing nudged the time slider left.

Onscreen, the door swung open and Chen Xufeng walked out. The two police on the bench immediately stood; Chen waved them an all’s-well and walked in the opposite direction. The point of view followed closely, as if someone were filming from right behind him with a camera. In the digital mirror, Chen Xufeng entered the restroom, took a handgun from his trouser pocket, pulled the trigger, and returned it to his pocket. Bai Bing paused the simulation here and rotated the view around to different angles as if it were a 3-D cartoon. Chen Xufeng walked out of the restroom, and the point of view followed him back to the office, revealing the four people waiting for him.

The Senior Official watched the screen expressionlessly. Lu Wenming raised his head warily and eyed Chen Xufeng. “That thing really is impressive,” Lu Wenming said with a dark expression.

“Next I’ll demonstrate an even more impressive feature,” said Bai Bing, pausing the simulation. “Since the universe is stored in the digital mirror on the atomic level, we can search up any and every detail in the universe. Next, let’s see what’s in Chief Chen’s coat pocket.”

On the paused screen, Bai Bing clicked and dragged a rectangle over the area of Chen Xufeng’s coat pocket, then opened an interface to process it. With a series of actions, he removed the cloth on the outside of the pocket, revealing a small piece of folded-up paper inside. Bai Bing pressed Ctrl+C to copy the piece of paper, then started up a 3-D model-processing program and pasted in the copied data. A few more actions unfolded the piece of paper. It was a foreign exchange check for 250,000 USD.

“Next, we’ll track this check to its origin.” Bai Bing closed the model-processing software and returned to the paused video window. Bai Bing right-clicked the already-selected check in Chen Xufeng’s coat pocket, then chose Trace from the list of options. The check flashed, and the still screen jumped to life. Time was flowing backward, showing the Senior Official and his retinue backing out of the office, then out of the building, then into a car. Chen Xufeng and Lu Wenming put on earphones, clearly listening in on Bai Bing and Song Cheng’s conversation. The trace search continued, the surroundings continuing to change, but the flashing check remained at the center of the screen as the subject of the search, seeming to tug Chen Xufeng with it through scene after scene. Finally, the check jumped out of Chen’s coat pocket and slipped into a small basket, which then jumped from Chen’s hand into another person’s. At that moment, Bai Bing paused the simulation.