(First Aired: January 29, 1967)
Screenplay by: Ryu Minamikawa and Tetsuo Kinjo
Directed by: Samaji Nonagase
When Japan is left perplexed by the sudden disappearance of every last ounce of gold at Mt. Ohtayama, the nation’s most bountiful gold mine, the answer reveals itself when the gold-eating brontosaurus-like monster Goldon bursts from the ground to devastate nearby mining villages. Science Patrol is informed of the situation, but they realize that if the beast is capable of burrowing, they’ll need to use Ide’s latest invention – the drilling tank Pellucidar. Muramatsu and Ide take Pellucidar, while Hayata, Arashi, and Fuji are instructed to stay aboveground on the Jet V-TOL. With their strategy laid out, Science Patrol moves into action.
At Mt. Ohtayama, the Jet V-TOL’s assault fails to prevent Goldon from burrowing away to safety. On the ground, Muramatsu and Ide are greeted by a miner, who informs them that his gold-crazy friend has been trapped underground for two days. With that in mind, Muramatsu and Ide head underground in Pellucidar. Underneath the earth, they come across a large natural cavern and find the maniac miner. The miner is taken on board against his will, where he tells Ide and Muramatsu to keep away from Goldon because the monster is filled with gold and he wants it all for himself. Then, Goldon barges into the cave, prompting Ide and Muramatsu to monitor its movement. Goldon remains unaware of their presence, so Pellucidar follows behind it, while the exhausted miner rests. Goldon finally notices them, forcing Pellucidar to use its defensive lasers. Goldon simply uses its brute strength to knock the drilling tank aside before leaving.
On the surface, the ground bursts open to reveal the returning Goldon. The Jet V-TOL takes on the monster with little effect. Hayata suggests that since Goldon is a subterranean creature, it must be weak to bright light, so they should land and throw a Corona Flash Bomb at it before firing away. On ground, the team carries out the strategy, successfully killing Goldon. Arashi reports the victory to Muramatsu, who informs the surface team that Pelucidar has been broken by its encounter with Goldon. The drill tank is now unable to stop tunneling downwards, lowering interior oxygen levels and increasing cockpit temperatures. Muramatsu takes to Pellucidar's controls while Ide does his best to fix the out-of-control vehicle. Ide finally fixes Pellucidar, allowing the drill tank to reverse its way out of the tunnel. However, the back of Pellucidar crashes into an enormous tail, which the crazed miner believes is Goldon. Although Muramatsu and Ide refuse to believe it, the lunatic miner tries to get out of Pellucidar to collect the gold in the monster’s body. Ide knocks him out and finds that the oxygen tank was destroyed by crashing into the now-disappeared tail. A little more reversal takes Pellucidar back to the cavern, where it turns out the miner was correct – a second Goldon exists! Worse still, oxygen levels are still decreasing rapidly on Pellucidar. Goldon’s huge size knocks the drilling vehicle on its side like a toy, leaving Muramatsu and Ide in a desperate state. Fortunately, they manage to fire a missile at Goldon, driving the monster away from them and to the surface.
On the surface, Arashi and Fuji have left to take care of their injuries at the nearby hospital. This leaves behind Hayata, who spots the surfacing Goldon and becomes Ultraman! Ultraman and Goldon do battle, and it ends when Ultraman fires the Specium Ray at the monster, ending the Goldon threat once and for all. Ultraman’s job is not done though, and the hero flies through Goldon's tunnels underground to rescue Muramatsu and Ide. He reaches Pellucidar just in time and places it on the surface before leaving. Muramatsu, Ide, and the deranged miner recover quickly. Afterwards, Science Patrols gathers back together and extracts the gold from the Goldons’ bodies, which they donate to the locals whose homes and livelihoods have been destroyed by the two monsters.
Tropes:
- Drill Tank: The Pellucidar is a futuristic-looking subterranean tank with a giant drill on the front.
- Flawed Prototype: The Pellucidar is strong against pressure from the front and back, but weak against pressure from the sides. After encountering Goldon, the tank gets damaged and nearly kills everyone on board.
- Hoist by His Own Petard: During their battle, Ultraman ties the second Goldon's Prehensile Tail around its neck, making the monster choke itself.
- Metal Muncher: Goldon feeds on gold. Reflecting its diet, its body is mostly composed of gold, and Science Patrol donates the gold extracted from their corpses to help the locals rebuild.
- There Is Another: Science Patrol destroys a Goldon, only to learn that there is a second Goldon within the mine.
