From the front of the book:
Darkness and light struggle and heroes are once again drawn to unravel the secrets of the radiant vessel. Can the truth be determined and the machinations of Szass Tam put to an end? This adventure is the conclusion of the “Radiance Against Thay” major quest and sequel to CORE1-2 Radiant Vessel of Thesk and CORE1-6 Incident at the Gorge of Gauros. A Living Forgotten Realms adventure set in Rashemen and Thay for characters levels 11-14.