Heroes rescue immortal kids scattered across the cosmos while killing anyone who gets in their way.
A team of heroes serving immortals of the "light" elves seek 27 "planar children" whose celestial natures are tied to massive world-generating magical spell. Those opposing this quest include Lolth, immortal leader of the drow "dark" elves; cultists of the Elder Elemental Eye and their giant minions; a mind-flayer mastermind; and a fey giant warlord.
The campaign premise adapts the Planescape setting into the D&D4e cosmology about a decade or two after the Faction War, detailed at the end of the setting's AD&D2e run. The factions which once ran Sigil, the City of Doors, have largely been exiled and replaced by a dabus-run government and the return of cross-planar guilds. Oddly, while most planar travelers claim to be familiar with the planes of the Feywild, Shadowfell, Elemental Chaos and Astral Sea, a few berks maintain memories of "the Great Wheel" when the cosmos ran differently. Other paradoxes remain: some doubt the devil-demon Blood War truce is real, while others claim active worship to deities believed slain during the mythic war against the great primordials.
War among the Elvenkind has raged for countless centuries across the planes. The drow armies of Lolth have conquered dozens of worlds, but a turn of fate has dealt serious blows to the Queen of Spiders' plans. Suddenly vanished is the world of Adeus, where Lolth had tricked theocratic human rulers into enslaving their own god. A betrayal by an obscure drow-eladrin halfbreed bard has allowed elven legions to retake a captured mortal world. Resistance is rising on the enslaved dwarven worlds of Maldev and Truegard. The Queen's web is unraveling.
Still the war continues. Recently a group of covert agents answering directly to the eladrins' Court of Stars have taken to traveling the planes in other to thwart Lolth's further schemes. Along the way the group discovered a list of children's names and a copy of the Ritual Primeval, an awesomely powerful spell which can create a new world. Each of the children embodied a celestial ideal, and their connection to use of the ritual pointed to troubling complications: To create a new world, the children must die. Now tasked with keeping such knowledge out of the hands of evil rivals, the heroes seek to protect thoses they have rescued and decide what to do next.
Lolth has not been idle. The demon goddess has allied herself with a conspiracy of giants who seek to free an ancient primordial, setting off a new cosmic battle not seen since the Dawn War. Better to end the world than let her hated enemies create a new one, or so her twisted worshippers believe.