After a rest, Professor Wilhelm used his teleporter to transport the team to the portal.
Peering out into the next cavern they noted it had four obviously manufactured roads, each leading to an exit, all of them dark. Some discussion ensued, but ultimately the team made for and entered the leftmost exit, to what looked like a staircase, though not one made for human use.
As the team crept cautiously down the stairs, the entire flight trembled, then collapsed as water surged into the tunnel to form a fast-flowing waterfall, sweeping the heroes into the next cavern. Once they were back on their feet, the team noticed that the water was warm, and tasted almost soapy. Grant, having thought to bring waterproof matches, relit Wilhelms marvellous lantern.
The adventurers set off downstream. Perhaps a few minutes into the hike, Hartwell spotted a light off to his right. Altering course that way, the team encountered a bank where they could climb out of the water and wring out their clothes before setting out anew in the direction of that light, which proved to be a passageway with a staircase leading upward.
As they began to climb, Grant froze in stunned amazement. Following his gaze, the others saw a natural breastwork, and crouching behind it four hideous, six-legged alien creatures, each about five foot long, maybe three foot high, massing about the weight of a young, healthy human. They sported a milky-white exoskeleton, two saucer-sized eyes and a vertical mouth.
Each had a breech-loading Remington rifle in its claws.
Though not able to understand a word of the vile clicking these things made, the gestures to drop all weaponry were clear and unambiguous. Grant huffed "Well, they've got their rifles trained on us, they're behind cover and they have the height advantage. I'm all for going along peaceably. How about you?"
With no other options, the others agreed and were soon under armed escort, and being led through more of the damnable lunar caverns.
Emerging into a series of caves with more of the strange "Selenites", the team were amazed when tghey were led to what looked like a terrestrial office with a desk of all things, behind which sat a man with unkempt hair and a beard in which one might hide a badger. This proved to be non other than the missing Russian explorer, Vladimir Tereshkova!
The man had clearly gone native, shoveling handful after handful of fungus into his mouth as he crowed over his new captives. As he raved and ranted it seemed he had discovered diamonds on Luna, and had brought rifles from Earth in order to recruit a guard force with which to intimidate the worker drones and force them to mine for him. He casually told the adventurers that he would take their aethership and leave them on the Moon to their fate, before having them confined in another cavern.
Here the team met with a third kind of Selenite, some form of leader caste named K'chuck, with whom they were able, after much back and forth, to find common cause. They would drive out the guards and capture Tereshkova, thereby freeing what were obviously the slave labourers to return to peaceful farming.
First order of business was to overcome the guards still overseeing the diamond mine. The team sneaked into the large cavern, formerly a fungus farm but now the site of furious mining activity. Although the cavern was full of Selenites, most were Drones. The guard force had been depleted when Tereshkova, eager to begin his plan, had set off to locate Grant's ship with a large contingent of his loyal guards.
Having retrieved their weapons, the team carefully made their way to positions of vantage, then began a fierce and hotly contested battle with the guards. It was a hard fought battle, but the Earthmen were not in the mood for nonsense and soon had all the Tereshkova-loyal Selenites pushing up green and grey fungus.
K'chuck announced that Tereshkova had been spotted making his way back to the Selenite community with his guards.
