Tremors in the Sand

From the introduction: Tremors have been heard and felt in the hot sands of a desolate and dangerous desert. A gifted mystic named Ilishara has received a vision from the dark powers to which she dedicates herself. This vision has beckoned her to summon the most destructive creature known to exist on this plane; the tarrasque. The beast lies beneath the sands of the desert, as Ilishara attempts to awaken the tarrasque from a small desert ridden temple with the aide of a tribe of Yuan-ti. Can the adventurers stop her evil plan in time, or will the tarrasque awaken and let loose upon the world?