So far, we know that these two games are a sequel to what we played last year. The story ended with the two heroic dragons caught and the sages imprisoned by the police, except for Ghetsis.

Now that the story continues two years after the original, with a new protagonist and rival, predict the new plot of the games and the role of different characters that appeared last year or are new.

There are certain questions that come to our mind:
Is N ever going to appear again?
Why is Unova frozen?
What happened to the earlier protagonist and his dragon?
How come the sages are back again?

Be creative and write your own plot!

Is N ever going to appear again? Yes. N will probably get the other dragon
Why is Unova frozen? My guess with with Kyremu around, it awoke and made it's den from ice.
Or it's just trying to keep us out from that area
What happened to the earlier protagonist and his dragon? Hmm... perhaps they flew off? idk
How come the sages are back again? The Shadow Triad might have helped them escape jail.

On serebii theres a pic that N is with you and seeing kyrem and team plasma's leader, so maybe he steals N's dragon or using a piece of DNA to turn kyrem into its new form.

Is N ever going to appear again?
Yes, but most likely as an adult. I guess his kid (If he ever has one) Will probably be the next villain, unless Ghetsis found some N look-a-like to be the villain.

Why is Unova frozen? My guess is Kyurem woke up and left his lair, creating massive blizzards wherever he went. Or, continental shift happened an now we're near the Arctic Circle.

What happened to the earlier protagonist and his dragon? I think he/she grew up. Whichever gender you pick, your parent will be the opposite gender from the first game, grown up. After you beat the game, you can go and fight your other parent (The same gender as you, older) sometime after you beat the game. There is no possible way we can look so similar to the previous protagonist unless we're cloned from them.

How come the sages are back again? The had bail money. Lots of bail money. Or, the escaped. Or, since they were so old to begin with, they passed away and now their ghosts have come back to haunt us.