Soulfire, the red ruin (Old Fiendish Red Dragon/Disciple of Ashardalon) has returned from his sojourn to the abyss. He seeks objects of power to fuel a ritual that he hopes will force the mighty Tiamat, queen of dragons, to recognize him as her chosen consort. If he succeeds, and Tiamat spawns here first progeny in millenia, the very heavens will be rocked to their core.
The 300 years he has been missing have caused the legends of his wrath and rage to fade into just that, legends. In this time, the kingdom has become a peaceful place. Farms and villages have sprung up a the very foot of the bleeding spire, once home to the "fiend who flies".
Soulfire now sits in his labyrinthine lair, scrying his old enemies, and gathering old allies. Even with power as great as his, he will need help to get the objects he so desperately needs.
A (theoretical list of epic objects) :
The heart of a planetar
The tears of a devil
A blade wielded in battle by a virgin queen
The soul of an innocent
A god's folly
Soulfire will have several agents assisting him with the collection, I propose one BBEG for each object. Examples:
An elder Salamander noble
An Efreet or Dao Lord
An azer or fire giant champion
A Demon or *gasp* obryth!
The party will encounter scouts and minions of these Lieutenants until they are appropriate level to tackle the bosses themselves. For proper scope, each of the objects should be located in a locale completely unique to each other, A floating castle, and angelic court, a sunken city, an abandoned mine/fortress, etc.
The rest is minor details, LOTS of random encounters appropriate to area, and improv! With the affairs of dragons involved, it will be an easy thing to involve the "good" dragons for a truly awe inspiring epic fantasy game.