The finale of Dark Crisis #1 reveals the members of the Justice League are trapped in a cosmic prison, following the team's defeat at the hands of Pariah.
The last pages of Dark Crisis #1 show Pariah standing amid the rubble of the battlefield where he faced off against Earth's finest heroes in Justice League #75. The climax of that issue ended with Pariah's mind-controlled troops -- which included the likes of Darkseid and the Spectre and were all corrupted by the primordial Great Darkness -- killing the League one by one. Pariah's final burst of anti-matter energy vaporized Batman, Superman and Wonder Woman, their deaths mirroring the demise of Barry Allen in the classic Crisis on Infinite Earths #8.
In spite of these events, Dark Crisis #1 reveals that DC's Trinity and the other members of the League are much more alive than the crowds mourning them on Earth believe. They appear to be stuck in alternate realities, and Pariah taunts that he plans to "use the deaths of the Justice League to destroy the Multiverse."