The following info comes via AnimeNewsNetwork:
"According to Animax and Marvel, the story is set one year after the death of Jean Grey and after the X-Men organization has effectively disbanded. However, Hisako Ichiki (Armor) — a mutant middle school girl living in northeastern Japan — has gone missing. An emergency call for help is sent, and the founder of the X-Men, Professor X, summons his team from all over the globe. The reunited X-Men travel to Japan where they encounter a supremacist cult called the U-Men.
The series will premiere on Animax on April 1. Animax already launched an Iron Man and Wolverine anime, and it is also planning an anime for Marvel's Blade character this summer. The American network G4 plans to begin running these four titles this year."