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Chapter 3:


ONCE THE CHARACTERS enter the large cavern, they will have truly entered the sub-Lunar world. There will be no clear trail to follow, and so the characters will be reduced to wandering and exploring, gradually making their way further and further down.


Luna experienced a planetary evolution unique among the worlds of the Solar System. It coalesced from an ancient mass of rock and debris with a high proportion of gases. These gases permeated the molten young planet, and, as the rock cooled and hardened, the gas bubbles remained intact, honeycombing the world. Eventually these gases leeched out of their separate caverns and combined to become Luna's subterranean atmosphere.

Allow characterrs with Geology skill to make a roll to come up with this theory. If they do not succeed, do not explain Luna's formation to them.


THESE CAVERNS, and their connecting tunnels and passageways, formed around gas bubbles when the Moon cooled and hardened. They are now the habitat of all life on the world.

Dry Cavern: Each dry cavern is from 50 to 1000 yards in diameter. Although spherical in general shape, their interior walls are very uneven due to large pieces having broken off and fallen to the floor during cooling. Over the ages the water vapor in the atmosphere has condensed on the roofs of the caverns, triggering the formation of stalagmites and stalactites.

Quite often the bubbles that formed the caverns touched, and the points of contact now form openings between the spheres. There are numerous cracks which formed during the planetary cooling as well, and water flow from one cavern to another has gradually enlarged these. Given the number of caverns and connecting passageways it is almost certainly possible to circle the Moon travelling through these tunnels and caverns.

Water Cavern: This cavern is identical to a normal cavern except that it is partially full of water. Water will enter the cavern from either a tunnel or small cracks in the ceiling. However, there is no exit for the water at the bottom of the cavern, and so it fills up until the water level reaches a suitable exit. This exit may be an opening to another cavern, or it may be a water tunnel.

Water Tunnel: Water tunnels are rock fissures which have been widened by water-flow erosion. They angle downward, usually at about 25 degrees, but may be shallower or steeper. Unlike the broken cavern walls, tunnels tend to be smooth and slippery, with at least a trickle of water through them (sometimes considerably more). Water tunnels will empty into either a water cavern or a dry cavern. If they empty into a dry cavern, there will be a large mass of muddy sediment at the point where the tunnel empties, and around it will grow a great deal of fungus.

Crevice: A crack in the Lunar rock caused either by cooling or by a Moonquake. It is usually very narrow, dirty, and jagged, as there is little or no water flow through it. Characters will have to remove most heavy equipment to wriggle through and then pull the equipment behind them by rope.


TO CONTROL the wanderings of the characters through the maze of caverns and tunnels, it will be necessary to make a map. It is not necessary to do so in advance; just make one up as you go. Since the players will probably be making one up, you may want to just make sure they are doing an adequate job and then use it.

Each time that the players enter a new cavern, you will have to determine the type of cavern entered, the number of exit points, and the types of exit points. Roll a die and consult the Lunar Terrain Table to make each of these determinations. A separate die roll is made for type of cavern, number of exits, and for each of the characteristics of each exit. Caverns may be wet or dry. Each exit from a cavern may be low, level, or high, may lead ahead, right, or left, and may be an opening (a roughly circular hole in the wall between two caverns), a water tunnel, or a crevice.

This is one of the most asinine things about this module; if the rolling is done in front of the players they will soon realize they are travelling in a random cave complex, without any rhyme or reason.

A smart GM will lay the caves out ahead of time, so as not to appear that the characters can just amble around aimlessly. The best way to do this is to map a series of "clusters", areas with a variety of connected rooms, usually separated by long passages. While the characters may want to search all the rooms adjacent to the one they are in, sooner or later they will leave the cluster from one bring them into the of a variety of exits. This will always lead them to the next cluster (or one of a pre-determined group); in other words, whichever way the characters go will be the "right way". You can certainly use the random tables below to create these "clusters".



The apparent difficulty of moving about in the maze of caverns and passageways is partially offset by the low gravity. Remember that the gravity at this level is about half that of the Earth, so falls are easier to avoid and not as serious when they do occur. Characters will spend about a half-hour in each cavern they enter. Each level or high water tunnel traversed will take another half hour for the entire party, while each crevice traversed will take an hour. Spelunking is very exhausting work and so the party should not attempt more than eight hours of travel a day. Animal encounters will continue as in the "Subsequent Days" section.

When moving between caverns by way of openings, some care is required. If the opening is level (the two caverns are at the same depth), then passage is easy. If the opening is a low exit, then it will enter above the equator of the next sphere, and characters will have to climb down the stalactites or the broken rock faces of the cavern to enter it. Lowering characters by rope is safer, if ropes are available. If the opening is a high exit, then the process is reversed: The players need to find a way to climb up out of the cavern.

Water tunnels are extremely easy to move through if they lead down from a cavern; they are just a nice long mudslide. They are also easy to move through if they are a level exit, although they are generally small enough that players will have to proceed on hands and knees. If they lead up out of a cavern, they are nearly impossible to climb due to the slippery walls and lack of handholds. A player may do so by rolling successfully against Agility five times in a row. (Each time he misses he slides back down and has to start over again.) If a water tunnel exits a water cavern levelly, the tunnel will be partially or completely full of water (at the referee's discretion) and will always lead to another water cavern.

The map on page 143 displays a section of the Lunar subsurface, an area which will be encountered later in the adventure. However, it is fairly typical and should be examined as an example of Lunar mapping. There are two views given, one from the side and one from the top, to make the spatial relationship of the caverns more apparent.

Cluster #1

The First Cluster should simply be a sampling of a variety of cave types, allowing the players to become familiar with the various types of caves they will encounter. Near the exit is a mark scratched on a dry piece of wall, which says "OUT" in Russian.

Cluster #2

The Second cluster will be much like the first, with two exceptions:
First, the party will find evidence of a camp having been made a long time ago by humans. Discarded food tins, the remains of a fire, etc. will show the players that they are indeed on the trail of Tereshkovitch and his men.
Second, the party will also discover the giant "Lunar Moths". These creatures have a large (2') wingspan, and a greyish-white fuzzy hide. Their wings glow in the dark with strange, luminous patterns. The feed on the lunar fungus and are harmless, though they will be inquisitive about the party (especially if they have brought light sources) and will flutter around "menacingly". They can be easily killed, and the remainder will likely scatter if one of the moths is killed. However, they are very forgetful and will periodically return to annoy the party. The pelts of the Lunar Moth are potentially quite valuable, as their fur is quite fine and is comparable to otter or mink.

Cluster #3

The Third cluster is unique because at it's centre lies a very large cavern (over 1000 yards in diameter) which is shaped like a flattened sphere. A pool of water roughly 200 yards across lies at it's center, which is fed by a very slow dripping from the ceiling. At it's center, on the ceiling above the pool (which is perhaps 250 yards up), a profusion of strange blue and lavender crystals hang from the ceiling. These crystals emit a quiet, barely audible hum and glow softly, illuminating the entire chamber.

Players may wish to investigate further, though getting a sample of these crystals will be tricky. A scaffold could be built from the stems of mushroom trees, but it would have to ascend an enormous height. Likewise climbing the walls will pose it's own problems, since most of the climb will involve the climber being forced to hang from an overhanging ceiling.

Some players might simply take potshots at the crystals with their guns. While this will cause some crystals to break or shatter, the pieces will stil fall into the pool. There may well be water snakes or river grabbers in the pool. Broken crystals will flicker and darken shortly after being damaged, though even a piece of such a crystal may still be of value to a geologist who wishes to study the mineral.

The full nature of these crystals may be left up to the GM, and if the players get the opportunity to examine them they may make one of many discoveries. The following are a variety of options available to the GM:
  • The crystals simply emit light, perhaps when under pressure. A Geologist could make a discovery into "Geoluminescence", allowing light sources to be made from the mineral or synthesized in a laboratory.
  • The Crystals have some value in Ether Mechanics, and may be used to augment the functioning of an Ether device. If so, an attempt to invent that device is given a bonus of +2 to the invention roll, but if the roll succeeds then the device must incorporate the Lunar Crystal into it's design, and will be difficult to reproduce because of the difficulty in obtaining these crystals.
  • The Crystals may be toxic, causing symptoms of radiation sickness (though the players won't know what radiation sickness is) or some other bizarre space disease.
  • The crystals are a rare silicon-based form of Lunar Life, and communicate to each other using etheric waves. They are generally immobile but can use their etheric energy to levitate and move around occaisionally. They defend themselves by emitting mild electric shocks when touched.
  • The Crystals are actually an artifact left by the Vulcans (moon men) who had considered building something in this cavern. They decided not to bother, however, and "left the lights on".
Whatever the Crystals turn out to be, the Selenites consider them sacred and will be disturbed if they find out the humans have damaged them.

Cluster #4

One of the caverns of the fourth cluster has what appears to be at first glance pieces of broken crockery everywhere. Further investigation will reveal the wall to have a variety of square ceramic "boxes" lining the walls, most of which have been smashed. Observant characters will also discover what seem to be spent Remington carbine cartriges here and there on the floor among the smashed porcelain.

There was once a Selenite villiage here, but a pack of Giant Caterpillars have taken up residence, and drove out the Selenite villiage a long time ago. 4-8 Giant Caterpillars are roaming the area, and if encountered will attack the party all at once. A well armed party might stand and fight, but smaller groups would probably be well advised to run for it. Tereshkovitch's party came through here, and shot their way through two years ago.

Cluster #5

This cluster will seem fairly ordinary, but the party will discover a tunnel entrance high in the wall of a cavern with perfectly smooth walls and straight lines. It has obviously been machined or otherwise deliberately tunneled somehow. Closer inspection of the walls will reveal scratch marks that would be consistent with some sort of rotating toothed device.

The tunnel will stretch for about 300 yards, and then enter a chamber about 50 feet in width. The chamber is circular, with a columned arcade around the sides. Under the arcade the ceiling is about 20 feet up, but in the center the shaft goes up at least 100 feet. The walls are carved with a strange, almost hypnotic rippling pattern, and are shot with flecks of reflective material, perhaps mica.

Hanging from the ceiling by a long cord that is made from some sort of silk is a glassy globe about 2 feet in diameter. It is filled with a blue liquid that has white bubbles and froth moving about slowly inside. slowly dripping from the bottom of the orb are drops of water (which seem to be from condensation) which land in a small basin in the center of the room. The basin is about 5 feet wide, and four feet deep. It looks about half full.

The purpose of this room will be explained later. It should not only provide an archaeologist with something to do but also will clearly indicate to the players that intelligent life exists on the moon, or at least did once.


AFTER SEVERAL days (the exact number being up to the referee) of wandering, the players come upon a cavern which has a well travelled path through it, and from which large boulders and stalagmites have been removed. The rising edge of the spherical cavern has grooves and steps carved in it to assist climbing, but the steps are very narrow and set closed together, making them difficult for mimans to use. What the player characters do not know is that they have come upon the outer caves of a large "nest" of Selenites, or Moonmen. The Selenites do not patrol these caves, since no other Selenites ever come this way. However, the player characters will stumble upon some Selenites in the caves and will probably be captured by them.

Set up the situation with the exhausted player characters resting in the well travelled cavern. They will hear scraping sounds coming from one of the exits of the cavern. When they investigate, they will find steps leading up to a high opening.

Cluster #6

The players enter a cave-cluster that is honeycombed with small tunnels, between two and three feet wide, only barely large enough to explore if the characters want to attempt it. They twist and turn and trend generally downward.

The party will probably get a little nervous, perhaps suspecting that these are Giant Centipede burrows. Soon the party finds a large Giant Caterpillar, perhaps 30% larger than the largest one they have seen so far, placidly eating fungi. The players have by this point probably adopted a "shoot on sight" policy regarding the centipedes, but if they avoid a fight the centipede will attack. While large and having lots of hits, it is rather slow, and will not do a lot to the players, though it may injure one of them.

When the dust settles, and the Caterpillar exhales its last breath, the players look around to discover that one of them (probably whoever was in the rear or held back in the fight) has gone missing. They have simply vanished, though things they have held in their hands may be on the cavern floor.

See below to find out what happened to them.

Bugs with guns!

As you begin to climb up the narrow, notched steps. Grant looks up and freezes in stunned amazement. You all look up and see, crouching at the lip of the opening and behind the natural breastwork that it forms, four hideous, six-legged alien creatures. Each one is roughly five feet long and stands three feet tall from feet to head. They appear to weigh about 60 pounds each (which would be 30 pounds in this gravity). Their bodies are covered by a translucent, milky-white exoskeleton, and their faces have two saucer-sized, multifaceted eyes and large, vertical mouths. Each of them holds a Remington breech-loading carbine in its front set of limbs. They make a series of whines and clicking noises, and gesture to the party to throw down their weapons and surrender.

Talk about a boring ambush. The players simply walk into a trap, even though they must be on constant guard for Giant Centipedes? And four Selenites armed with Carbines aren't going to seem like a big threat to many parties. A large party will probably want to shoot it out and count on superior numbers and firepower to win the day. Even smaller parties might not want to be taken alive by giant bugs with guns.

Here is a much more exciting option:
Make sure that you have a marching order for the party ready; in fact, this should be kept at all points through the underground adventure. As the party makes it's way through Cluster six, they will begin to encounter the honeycomb caves. What will happen here is that whoever is in the rear, or whoever fails an observation test, will suddenly be grabbed by the ankles and dragged with lightning rapidity into one of the tunnels.

Naturally this will startle the rest of the party if they notice it at the time; if they do not, suddenly one of their number will go missing. The Selenites will grab party members one by one, and drag them into the small tunnels, which are only barely big enough to fit a human through. The party should be made to get more and more paranoid, until only one or two of them is left, and then the armed custodians will make their appearance. The players will be more willing to surrender knowing that the Selenites can probably lead them to their companions.

Meanwhile, the kidnapped players will find themselves dragged very quickly down a long narrow tunnel. It is very difficult to do anything in these tunnels, as they will be bashed and banged around as they are dragged along. Side tunnels will branch off here and there, and the player will quickly become lost and will not be able to find their way back if they escape.

Upon emerging from the narrow tunnel, the player will find himself surrounded by armed Selenites, and will not be in a position to resist. Should the player start shooting while in the tunnel, the selenite captors may spit a sticky goo onto his face that renders him blind, or they may lose the fight. They will not try to overtly harm the character. Each character is dragged by two Selenites, and if one is killed, the other will run away, abandoning the character. However, the selenite, wounded by gunfire, will leave a slimy blood trail that the character can follow. Otherwise, he will be trapped in a dark, narrow tunnel with no way to find his way back. If he insists on stumbling around in the dark, he will continue until the character becomes panic-stricken, and at this point he will stumble on the chamber where he would have been brought initially, and quickly surrounded by armed Selenites.


Grant throws down his revolver and comments, "Well, they've got their rifles trained on us, they're behind cover, and they have the height advantage. I'm for going along peaceably. How about you?"


Once again, Dr. Grant makes a key story decision on behalf of the party. There is no way that this should be up to him, although being a fairly peaceful guy he doesn't like the idea of a shootout. Allow the players freedom to decide what they will do when faced with capture. If characters get into a fight and pass out from wounds, then so be it; they will end up captive anyhow. If a character escapes capture, make sure he is the only one to do so; he can influence the adventure as the "man from outside" at this point. However, if he ventures too close to the Selenite villiage before the revolution begins, then he risks being captured anyhow.

Detailed Start | Quickstart | The Descent | Within Luna | Captured! | The Escape | Selenites