The Justice League has the map to the Sixth Dimension in hand-and with it, they have the key to saving the Multiverse from utter destruction! Meanwhile, Superman is trapped on a world with no light and hundreds of dead Supermen! The Multiverse is teetering on the brink, and Lex Luthor�s Legion of Doom is poised for victory. The final form of Perpetua takes shape, and the DCU will never be the same again! Collects issues #19-28.