Ep. 6: The Underground City
Aired on May 21, 1981
6
Episodes
- Ep. 2 · The Infinite Universe
- Ep. 3 · Thieves of the Millennium
- Ep. 4 · A meteorite vanishes without a trace
- Ep. 5 · The Underground Boat Is...
- Ep. 6 · The Underground City
- Ep. 7 · Invitation to the Secret Base.
- Ep. 8 · Underground explosion crisis
- Ep. 9 · Investigating the Mystery Surrounding the Large Cave
- Ep. 10 · A battle occurs within the sacred cave location.