The boys meet scientist Mark Christopher and his friends who intend to remain in Carlsbad Caverns until a predicted nuclear war is over. Filming Location: Carlsbad Caverns, New Mexico
| Name | Type | Role | |
|---|---|---|---|
| Stirling Silliphant | Writer | ||
| James Brown | Guest Star | ||
| Lili Kardell | Guest Star | ||
| Conrad Nagel | Guest Star | ||
| Carol Seflinger | Guest Star | ||
| Phyllis Hill | Guest Star | ||
| Leslie Nielsen | Guest Star | ||
| Jimmy Carter | Guest Star | ||
| Fay Spain | Guest Star | ||
| William Woodson | Guest Star | ||
| Elliot Silverstein | Director |