From the Back Cover:
Traveling the space lanes is risky and mysterious, and danger comes in many forms. The rescue of a tiny ship from pirate attackers leads to the discovery of a monumental, supernatural evil. Nothing is ever routine in space...
Crystal Spheres takes the player characters through four unique crystal spheres to battle a powerful force of darkness. Player Characters will find themselves fighting not just for their lives, but the fate of an entire solar system and its millions of inhabitants.
Crystal Spheres is an adventure for the AD&D SPELLJAMMER campaign setting. The SPELLJAMMER boxed set is required to play. This 64-page adventure will easily adopt to any campaign world.
This adventure is designed for four to eight characters of levels 5 to 7.