A-Next is part of Marvel's new MC2 line, a new line set 15 years ahead of the current Marvel continuity. In this future, everything turns out fine, contrary to other storylines that presented us apocalyptic futures.
A-Next covers the afventures of the new Avengers. All the members (with the exception of Mainframe) are young and inexperienced. And all of them have ties to heroes of the current Marvel Universe.