After exploring a little the japanese site I found something about the main plot that more or less is like this. I used google to translate everything so I got the idea, If someone here talks japanese please help
Formed to protect both humans and mutants, the X-men had become inactive since the battle against the secret society of the "Inner Circle", where their teammate Jean Grey was killed a year ago.
Meanwhile a high school mutant goes missing on Japan. Professor Xavier, senses that this might be a larger problem than it seems, calls the remaining X-men back. It's time to form the team again.
The X-men fly to Japan where they met the U-Men and find some information that the U-men might be involved in the disappearance. Knowing their responsibility of becoming a bridge between humans and mutants, the X-men decide to battle against the forces of evil.
Hisako is a young high school japanese girl that is missing. In New York, Hisako's parents seeks help from X-men founder, Professor Charles Xavier, feeling a bigger story behind the disappearance of Hisako.
A year ago, after a fierce battle against the Inner Circle, the X-men were inactive but join forces again to search for the missing mutant.
But Cyclops, Jean's lost lover and leader, refuses to return.
Again, this is not the exact plot, but I tried to give it coherence to what I got from the google translator
So, it seems (and I repeat, it seems) that:
- The main X-men will be the ones that we already saw: Cyclops, Wolverine, Storm and Beast.
- The Inner Circle aka the Hellfire Club is the responsible of Jean's death.
- Based on the previous points, Emma Frost is most likely a member of the inner circle that fought against the X-men (But I hope that she reforms, joins the X-men and convince Cyclops to come back, lol, almost impossible, since in this story, her involvement in Jean's fate is more tragic than in the marvel canon... RIP Jean
- Cyclops will return as a the big emo guy, crying over Jean every five seconds (as in Wolverine & the Xmen)... Seriously... again? (and for that I'm going to change my signature so, I can express my point better with a funny quote
I want to watch this lol, sounds promising to me, even if the U-men are the main villains http://www.animax.co.jp/marvelanime/x-men/intro.html