A flash of golden light streaked past, and Barry appeared in Schiller's office. He let out a long breath, then collapsed onto the sofa beside him.
Schiller walked to the water dispenser, poured him a glass of water, set it before him, and said, "Worn out?"
"Not too bad." Barry drained the glass in one gulp, wiped his mouth with his sleeve, and said, "This time, it wasn't just me. Clark's brother—Hal—helped out a lot."
"Where did you learn the technique to reboot the universe?"
"From that Flash—uh, let me think—the Flash who created Thomas Wayne. Their universe had been rebooted before."
"What made you want to learn it?"
"You always need some insurance." Barry spread his hands. "That trip through time was pretty dangerous. If it failed and we couldn't deal with Hal, Earth would've been destroyed. I had to learn how to reboot things beforehand, just in case. Otherwise, how could I dare make a move?"
"But this didn't seem quite like a reboot. It was more like turning back time. Did you make some innovations yourself?"
"Not really. Hal was just more capable." Barry smiled. "If I rebooted things, I could only force a hard reset, and I wouldn't know which point in time we'd return to. But he can control time. As long as he takes a segment of time and plays it backward, he can create the effect of time reversal."
"It sounded complicated, but the results were certainly good."
"Exactly. The difficult part was preserving certain people's memories. Over the past few days, I ran all over the world and marked everyone whose memories needed to be retained. I had to be extremely careful during the rewind. I was afraid of damaging their brains."
"So when you came to see me that day, it