Callisto, Jupiter's fourth moon, is a peaceful world until the fatal day the mysterious subterranean disturbances begin. The terrified populace jams the spaceport, and a mass exodus takes place. When Johnny investigates, he discovers that the quakes are being caused by Nero Tyrantor, who is mining Callisto's core for platinum.
| Name | Type | Role | |
|---|---|---|---|
| Peter Fernandez | Writer | ||
| Sid Jacobson | Writer | ||
| Alan Riefe | Writer |