From opening paragraphs:
This lair was once the temple dedicated to a god of agriculture and community. It had a small but loyal congregation and was situated far from large urban centers. Due to this isolation, the necromancer has been able to work his dark arts in relative security and without much interruption. A GM may run this lair with little modification if he wishes it to be dedicated to another god.
The high priest of this temple still resides within, trapped as a malevolent, twisted undead creature. The necromancer who has made this his lair was able to corrupt some of the acolytes and laity into his service and they too still reside on the grounds.
The temple site, its basement level, and the caverns beneath are practically empty of life, except for a few vermin and molds, and instead have been replaced with all manner of undead atrocities and constructs.