From the announcement:
Greetings HeroClix Fans!
Things heat up this winter as the ultimate battle for the fate of the Earth begins as Marvel Comics’ successful Avengers vs. X-Men (AvX) storyline event comes to the tabletop thanks to HeroClix! Players will need to choose if they stand with Earth’s Mightiest Heroes, the Avengers, or with the Children of the Atom, the X-Men, in four exciting monthly events in this latest HeroClix Storyline Organized Play event!