We know that after the events of flash point paradox, flash created the new 52 time line aka prime-earth, but it also changed the history of a distant world known as remnant, giving it's people a brighter future, but also both worlds will collide!

Yang and ruby were going through the emerald forest, yang then found a mysterious green glowing rock, which she then put in her pocket, but they didn't know they were being watched!

Alien scientist:we shall bring these humans back to the world of their progenitors!

Immediately a boom tube opened and sucked them in.

metropolis

yang and ruby were immediately thrown onto a sidewalk in a large city they didn't recognize.

Yang:were are we?

Ruby:I don't know.

Superman was flying through metropolis when he saw a boom tube open and release two figures. He flew towards them immediately.

Ruby:yang I see someone flying!

Yang:yeah right!

Then yang saw it too.

Yang:what?!

Superman:who are you and why did you come here?

Yang:we were sucked into a portal all of a sudden! By the way do you know what this is?

She takes out the green rock she found.

Next time yang vs wonder woman!

Explanation:remnant's inhabitants are the result of an alien experiment where they wanted to test human's adaptability to environment by putting them on a hostile planet with a mystical atmosphere.