Alduin was slain. The last Dragonborn was victorious. Skyrim was liberated from the Aldmeri Dominion and had seceded from the Empire of Cyrodil. It seemed, for a time, that there would be lasting peace, but it was not so. During it's adventure's, the Dragonborn had pledged it's eternal soul to many entities, including each of the Daedric princes and several Aedra in order to gain enough power to defeat Alduin. Though the gambit was a successful one, it had unforseen consequences. When the Dragonborn killed Alduin, who was an aspect of Akatosh, the seals on the gates to Oblivion began to weaken, and the Daedric princes readied themselves to march into Tamriel and fight for the prize of the Dragonborn's soul.
Eventually, the Dragonborn died, unleashing chaos upon the world. With the last Dragonborn's powerful soul in a sort of limbo, the gates to Oblivion exploded open, and the armies of each of the Daedric Princes poured forth to do battle for the soul of a Dragon. It has been ten years since the Battle of Armageddon began, and a group has been gathered together to stand for mortality, in a last-ditch effort to awaken the Giant machine-god Numidium in the hopes that it could beat the Daedric princes back into Oblivion.
So, basically, the idea still needs some work, but essentially we'll be playing a rag-tag band of warriors rogues and mages who have gathered together to try to put an end to the war of the Daedric princes by awakening a possibly more dangerous secret weapon. Any interest or questions?