Midtown, police station.

Joe and Barry get in the car and begin their investigation. After Tang Tian told some secrets, he made up his mind to investigate the past case.

On the asphalt road on the outskirts of Midtown, a car stopped in front of a house, and two people came out of it, it was Barry and Joe. West.

"Barry, do you feel scared when you go back to your old home?" Joe turned to look at Barry and asked him.

"Before, it may have made me a little desperate, but now it is enough for you to help me." Barry said to Joe, gratefully.

Joe patted Barry on the shoulder and said encouragingly, "Barry, I swear that I will return your father's innocence, and tomorrow I will go to Star City to conduct an on-site investigation."

Barry nodded to Joe, they looked at each other and smiled, and Joe knocked on the door, the house was Barry's former home.

"Knock knock!" Joe didn't knock a few times, and a middle-aged woman in pajamas came out of it, and after opening the door, she didn't ask anything, but first threw a wink at Barry and Joe.

"Forehead......" Barry's expression was full of chills, as if he had eaten a fly, but he barely maintained a stiff expression.

Because the clues to investigate the mother's murder are inside, it is impossible for them to back down. Seeing Barry's expression, Joe walked out and said to the middle-aged woman in front of him, "Hello, ma'am, there was a case in this room before, we need to investigate, can we go in and investigate?"

"It's okay, I'm living alone." The middle-aged woman said "meaningfully" to Joe, and even Joe's hand that was about to take the police officer card was involuntarily put down.

When Qiao heard this, his face couldn't help showing some cold sweat, but his good quality made him nod and said, "Then thank you for your cooperation, lady."

When Barry and Joe walked in, Barry looked around the house and sighed, feeling a little sentimental about what was wrong with things.

Joe took the file and explained to Barry in detail the location and direction of his mother's murder, as well as some of the details.

"Alas, it's been a long time, it's been fourteen years." Barry said helplessly, knowing that the change of time had made a lot of crucial evidence disappear.

"That's right, Barry, but you noticed no, only the front mirror hasn't changed." Joe carefully compared the photos and said affirmatively.

Barry walked towards the position of the mirror, an object that barely changed in the photo, with a thoughtful expression.

"Wait, Joe, what's the raw material for the back of the vintage mirror?" Suddenly, Barry had a flash of inspiration and immediately asked, as if he had thought of something.

"Silver nitrate." Joe said with certainty that as an experienced police detective, he knew a lot of things, so he reacted immediately.

"Silver nitrate is mostly used in photography and the back of old-fashioned mirrors, if this is the case, then the electromagnetic sparks generated by the speedsters, the flashes caused by the flash are constantly exposed to the silver nitrate, then the key image we need is on the mirror."

Barry smiled, he was obviously excited to find these crucial evidences, and he was still one step closer to the breakthrough.

"Sisko's equipment can restore the original scene, which helps us a lot." Barry was pleasantly surprised by the team behind him, and it might be better to ask Sisko to help.

"Alright, Barry, you go find those images, and I'll go to Star City to check them out." Joe nodded to Barry, and they left the room with mirrors.

At the same time, Star City Base 34, the control room.

Betty walked up to Tang Tian in a military uniform with a document and said to him solemnly, "Sir, we found Barry. Alan and Joe. West went inside the house once and left with a mirror. ”

"Well, go down! Betty, I see. Tang Tian nodded thoughtfully and ordered Betty.

"Yes, sir." Betty said respectfully, and left the control room.

"They're about to unravel the truth, what role should I play?" Tang Tian smiled meaningfully and looked in the direction of Midtown.

At this time, Hartley also walked in, looked at Tang Tian's thoughtful expression, and said with a smile: "You seem to be very concerned about the cutting-edge laboratory, is it that they have also discovered Wells's secret."

Hartley's eyes flashed with anger, and he was still a little angry that Wells had kicked him out of the cutting-edge lab.

"Hartley, you're right, that's the case at the moment." Tang Tian smiled and explained.

"So what role will we play?" Hartley asked with interest.

"Wait and see." Tang Tian said affirmatively.

Tang Tian didn't feel the need to intervene in the relationship between Barry and Reverse Lightning. He himself doesn't like to meddle in his own affairs and get himself into trouble, unless there is a entanglement of interests, he doesn't care about anything else.

"By the way, I have something for you to see. I am very researched with sonic weapons, and as long as I find the resonant frequency of an object, I can almost destroy matter. Hartley said confidently.

"Of course, man, I trust you." Tang Tian patted Hartley's shoulder and said with a smile.

"Your sonic weapons have a lot of potential, and I'm more optimistic." Tang Tian patted Hartley's shoulder and said with a smile.

What Tang Tian knows is that Hartley's sonic frequency resonance potential is very high. If thoroughly developed, then destroying any material structure is a breeze.

For example, at the beginning of the 19th century, a group of Napoleonic soldiers marched through a bridge in the French city of Angers at the command of their commander. When they were about to reach the middle of the bridge, the bridge suddenly shook violently and finally broke and collapsed, causing many officers and soldiers and citizens to fall into the water and die. After investigation, it was found that the culprit of this tragedy was caused by the same resonance frequency.

Because when the soldiers of the brigade walked in unison, a frequency was produced that coincided with the natural frequency of the bridge, which strengthened the vibration of the bridge, and when its amplitude reached the maximum until it exceeded the pressure resistance of the bridge, the bridge broke.

The same is true of Hartley's sonic weapons, when the frequency of sound waves is equal or close, and the resistance of matter is not enough to consume the energy that excites them to stimulate each other, then the vibration of the whole matter will be unstable, and the vibration amplitude (amplitude) will increase and increase, until the object is completely destroyed.

Tang Tian is also optimistic about Hartley's research direction, and in the second season, Hartley used the principle of sonic resonance to repel the pursuit of Barry. Allen's time undead can be said to be not powerful.