Astrea is kidnapped with the intent to use her to power an underground civilization against her will. Hercules, Mercury, Sentinel One and MO use their spaceship to burrow their way to the city to rescue her.
| Title | Voyage to the Inner World |
|---|---|
| Genres | Sci-Fi & Fantasy Animation |
| Release Date | 1977-11-05 |
| Episode Runtime | 00 Hours 22 Minutes |
| Season Number | 1 |
| Episode Number | 9 |
| Production Companies | Filmation Associates |
