The Flash, Season 6

Cisco:
The Monitor? Where did you see him?

Barry:
We went in the Time Vault, right after putting Chester in the MAC. The Crisis that he spoke about last year, it's the same one in the plinth's newspaper. And it's not coming in 2024. It's coming December 10... 2019.

Ralph:
Are you sure about this?

Killer Frost:
The jackass lied to you.

Iris:
Yeah, well, we thought so, too, but... Barry went to Earth-3 and Jay Garrick helped him see that it was true.

Cisco:
How did he do that?

Barry:
Jay projected my mind forward into the future.

Cisco:
Okay. And what did you see?

Barry:
I saw a giant wave of antimatter sweeping over our Earth. Vaporized all of Central City and everybody in it. Including you three.

Killer Frost:
Great. I'll go mark my calendar.

Barry:
We still have seven weeks to make sure none of this happens.

Iris:
Guys, Barry's right. We've changed the future before. We can change it again.

Ralph:
So what else did our Asgardian cosplayer say?

Barry:
That was pretty much it.