The PCs are 5th level when this starts. They're hired by the Legion of Steel to stop a Chemoshian (?) uprising in the High Clerist's Tower (the Chemosh priests slaughtered the gully dwarves, reanimated them, and sent them south to Solamnia proper). Anyway, the PCs eventually get there and stop the Chemoshans just as the Chemoshians are fighting this red-haired woman (Mina) who's carrying off their obsidian altar.
The PCs eventually discover that Mina has found out about the Obsidian Chest, and she's trying to recreate it. Since the chest supposedly fashions an item that's specific to the individual, Mina's hoping that it will give her something that can be used to resurrect Takhisis. The PCs have a number of options - do they try to gather the chest for themselves, hide the pieces from Mina, do they dare try to find Takhisis' body and destroy it so she can't come back, etc.
Whatcha think?
Thought I'd throw in some ideas your way (if ya don't mind...)
Perhaps the chest that was buried under the High Clerist Tower, was some sort of ancient relic that was hidden there when the Tower was first built and the records were lost during the Cataclysm (heck, maybe they built the Tower to keep the thing hidden).
Perhaps make the chest an ark that the Chemoshians carry onto the battlefiled (Like the Ark of the Covenant in Raiders of the Lost Ark) and when they open the lid the souls of the angry dead fly across the battlefield screaming and inhabiting the dead on the battlefield creating ready reinforcements for the Chemoshian army, while imprisoning the souls of the dead who have recently died.
Perhaps the artifact has grown in power feeding off the River of Souls and it is this influx of power that was recognised by Chemosh and his minions. Perhaps if the object steals the souls, then Mina may believe it has Tahkisis' soul trapped within and that is why whe is stealing it (or perhaps she wishes to take the ark into the abyss -or wherever Tahkisis souls resides and free it from it's damnation using the item).
Perhaps the campaign adventure could be similar in fashion to the Lord of the Rings, where the party has to find a way to destroy the artifact while everywhere they go it animates the dead to do Chemosh's bidding. Perhaps Chemosh had his own plans too (just like Tahkisis) and this is all part of HIS plan to dominate Krynn. Maybe he planted the seeds in Tahkisis' head aons ago (she must have learnt the siphoning off souls and necromancy knowledge somewhere!) and his plans are just starting to come to fruition
Just a few ideas
Arandur
It sounds like a decent plot -- I would assume that the Knights of Solamnia & Neraka are also involved? I thought both groups were trying to claim the High Clerist's Tower for themselves, at least that's what's happening in my game.
Next question 'Whaitisit-and-whatsitdooo-and-wheresitcomefrom'?..
Arandur