In a Previews interview with Dan Jurgens and Jeff King, we learned a few things…

Firstly, there's a mix of Alan Moore's Supremacy and Grant Morrison's Batman, with a multi-dimensional Brainiac preserving continuity before they are retconned away. Everything happened.

That Brainiac has a "collection of more than 40 doomed "worlds" from across 75 years of the DCU" which he pits against the other."Convergence shows you where those heroes went, what they have been up to since Brainiac bottled them and whether they will ever return from "where world's go when they die.""

Oh and as to the worlds, "they are domed (versus bottled)."

That those who want to prep should pick up:

DC Universe Presents: Challengers Of The Unknown #7

Superman: Doomed #2

Futures End #1

#1 Futures End Booster Gold #1

Justice League International Annual #1

Futures End #22

Action Comics #35

Zero Hour

Red Son

Kingdom Come

Flashpoint

And Jurgens promises "There will be consequences to this story– very real aspects that will stick in the DCU. The ramifications will be quite tangible… There's a particular double page spread — or should I say, series of double page spreads — that make quite a statement."