From back cover:
The Moons of Krynn are fading. The alignment forces of Good, Evil, and Neutrality are locked in conflict... and evil seems to be winning! The unnatural machinations of the treacherous Khardra—daughter of Takhisis herself!—have led to a crisis of cosmic proportions. The Heroes journey to the Cloud City Cirulon, heart of the Good Dragon races, there to meet the Astral Dragon himself. The nature of a plague claiming the lives of silver dragonhood is revealed, and the cure is presented to the companions. But the road to success is fraught with peril, the only route leading through a secret portal. If this portal becomes known to the forces of evil, disaster will surely result.
This AD&D adventure, set in the world of the Dragonlance saga, follows In Search of Dragons. Some burning questions are answered but more are raised. And as the players investigate, the knowledge they gain seems to point more and more to a sinister thereat of evil undreamed of since the War of the Lance.