Duel Over Domana

From the Introduction:

Duel over Domana is a standalone encounter designed for five characters near the levels of 11 to 13. As far back as the bards can remember, the plains of Domana have known an endless war between two wizards, Azru and Risham. Night after night, year after year, their ancient duel continues - too equally-matched for a victor to emerge. However, their magic has become more destructive by the day, and the nearby town of Tocasis bears the brunt of every stray fireball, loose monster, and spell gone awry. As the damage to Tocasis worsens, the residents begin to wonder which will reach its end first: the duel, or their town?