Intro Scene: Timeline Turner

"It's not right."

"Mack-"

"They need to be prepared."

"It's not like we can destroy that weirdo. That'll cause major destruction. You can't tell them."

"Why not?"

"You know why. If that person knows about us, that's already a problem."

"Well what if they meet?"

"It's like asking for hell if those two are face to face."

And that's just for starters. What will happen when the mysterious threat isn't the only thing to cause change?