The players were escorting a planewalker to an ancient abbey to undertake some sort of epic spell. As the ritual took place the abby came under attack bu a spellweaver , rakshasas and cosmic barbarians. A massacre ensued and the players grabbed a mysterious artifact(looks like Chinese parade dragon for 4 dancers.
They escaped into the supernatural winter and just as they arrived at civilization collapsed in fatigue.
They found themselves transplanted to another dimension(going from 5th L Pathfinder chars to 1st L OD&D chars). Finding themselves in the Bat Cave some years in the future. The dungeon was decorated with mosaic of the pc's throughout, Eventually they encountered a Sphinx that was too smart to talk to. Quik thinking lead to getting him to write things down. He revealed that the universe is collapsing due to the destruction of the abbey. and that a point in the future they would have to return to the dungeon and save the universe by merely switching 5 leavers in the dungeon, they were also told that dif sections of the Bat Cave had dif planer realities(IE they would be playing multiple rules sets w. new char sheets as they moved through it,)
AS the universe is collapsing and the Confederacy(good and the Alliance are in turmoil fighting each other and in a hopeless battle to stabilize the dimensions.In a frontal assault on the Spellweavers both the Confedarcy and Alliance have taken tremendous losses in troops ,planeswalkers and Gods.The leadership of the Confederacy is dead scattered and just plane missing. Refugees are flooding the most stable of the Confederacy's dimensions but the planeswalking walls both side erected have collapsed and every plane is on the front line of the war. A mystererious and powerful planes walker has asumed control of the Alliance and knows the PCs their destiny, to save everything , although he is seemingly putting them off in compleating that destiny for unknown reasonsThe PCs helped stop an invasion of a fortress dimension ,that now is acting as HQ, they are in the middle of rescuing POWs from the Vampires , who seem to have taken over control of the Alliance from The Spellweavers.