Game Twenty-Seven: The Brains of this Operation...

In the 27th game in Dragonreach, a band of heroes were hired by the Arcane Conclave to check on a missing guild member (Kalerel Strom "of the Seven Howling Gates"), who had not emerged from his home for several months.  

A rival in the guild (Ravinnia Cruelcall) further hinted that, if it turned out the wizard was dead (wink, wink), a bonus would be paid.

The place was infested with dire rats, and the wizard had clearly been engaging in unwholesome experiments involving doppelgangers and extracting brains and replacing them in jars.   

The party opened a series of gates to the Abyss (which was some sort of elaborate home-security system), and had to contend with mischievous pixies and an angry minotaur and cockatrice that they released...

But, eventually, the party found the wizard, who had extracted his own brain and placed it in a jar.  The party killed the resulting horror in its lightning-filled workshop, losing only one member of their band in the process.