The Glass Giant

When the Van Horn expedition attempts to cross the Sarpedonian Desert on Callisto, their vehicle breaks down and they radio for help. Johnny and his friends pick up the SOS, and they head for Callisto. Because of the urgency of the call, Johnny goes on ahead, and Zena and Rhom follow in the Satellite. Johnny is able to fix the broken down vehicle, so the group sets out across the desert. Sometime later, they encounter the legendary City of Glass.