In the second volume of The Obsidian Age saga, the JLA continue their mission to save Aquaman from his imprisonment 3,000 years in the past. But when Batman, Superman, Wonder Woman, Green Lantern, Flash, Plastic Man and the Martian Manhunter go up against the Ancients, a powerful and vicious group of beings that predate time itself, each member of the JLA is mercilessly killed in battle. Now it is up to a replacement group of heroes led by Batman's former partner, Nightwing, to defend the future against the return of this ancient civilization and avenge the deaths of the world's greatest heroes.