In Faith for Entrell: Calinnes se Entrell (2007)

A One-Round Living Greyhawk Regional Adventure set in The Kingdom of Nyrond

From the introduction:

An old man sits in his darkened study contemplating his options. The stillness earns him some serenity in spite of the voices from the hall. A light rap precedes a flood of light as the page opens the door. “Master? He has arrived.” A grey elf wearing robes enters. With a slight gesture he touches a spent candlewick, illuminating the room with magical light. “Did you come to the same conclusion, archmage?” the elf questions. “Yes,” is the man’s distracted reply. The elf nods then turns to leave. “My apologies,” old man pursues. “I hope we understand each other, Melf?” Melf does not turn to face him. “Yes, Ghiselinn. We must break the seal, and I must tell a friend more of his people will die.”

A one-round Regional adventure set in the Underdark beneath the Kingdom of Nyrond for characters level 1 - 13.