Adventure: Beneath the Sands

Beneath the Sands Adventure Download

This adventure is designed for use with the Pathfinder roleplaying game; it takes the party to an ancient location for an old-fashioned dungeon crawl that provides hints of a growing threat to the solar system. While it is written for a party of seventh-level characters, and intended as a sequel to the scenario At a Crossroads, it can easily be adapted for parties with more experience and/or as a standalone scenario.

Adventure Background

Recently the PCs, while competing in an aethership race through the asteroid belt, made a curious discovery: a lost Royal Interplanetary Company cog, one that was outfitted for some kind of expedition surface-based expedition but that had somehow become frozen in a comet's ice with an angry nabasu demon on board. This vessel also contained a ship's log, one that can perhaps lead them to the place that the missing crew was hoping to excavate.

For the Gamemaster

Just about one year ago, agents of the Royal Interplanetary Company were sent on a secret mission to explore a tunnel network on the cold red desert planet. It did not go well. In addition to learning that the planet was infested with remorhazes, they found that a ziggurat deep in the tunnels had even nastier inhabitants. Repulsed by the demon worshiping troglodytes, and with one of their own succumbing to possession by a shadow demon, they fled. While they managed to trap a nabasu demon by securing it in dimensional shackles, the shadow demon eventually slew them and then returned to its lair. Now the demons and their minions lie in wait, ready for more interlopers.

Even more notable is the fact that these very same monsters serve the power known as Mother whose scheme for domination is spreading throughout the solar system. Indeed, this ziggurat has served as a base of operations for her, and the PCs can learn a great deal about her growing threat—if they can survive this one first, that is.

Part 1—A Conflict of Interests

Before they can head out on this expedition, however, the PCs need to deal with some business in Crossroads; a few of the issues most likely to arise are detailed below.

The Journal

First and foremost, the PCs need to make some sense of the journal that they found aboard the Constant. Show the players the handout in the appendix and let them do some figuring. Given those details, they can with a DC 15 Profession (sailor) or Knowledge (geography) check determine that, at that time, the comet would've been approaching the asteroid belt after circling the sun; the most likely candidate is the cold red desert planet that is neighbor to Homeworld.

Reda's Claim

If Luciano Reda hears about the journal's contents, he reacts strongly. For one thing, he claims that, because the Constant is a Royal Interplanetary Company vessel, he should be granted salvage rights to it. That is not true, however, a fact that can be confirmed with a DC 10 Profession (sailor) check. Assuming that the PCs don't just yield their salvage rights, Reda then resorts to different tactics. He is willing to pay the PCs 2000 gp for the wreck and everything aboard it, and increases that to 3000 gp if the PCs can beat him in opposed Diplomacy checks. Alternately, he is willing to pay the same amount if the PCs will undertake a voyage to the mysterious desert world, in order to learn what happened to the rest of the expedition. Indeed, he suspects that his brother Lorenzo may have been involved in this business, but he does not know for certain. For that reason, he wishes to send Lt. Vanderwald and a squad of R.I.C. soldiers with the PCs.

Outfitting and Recruiting

The PCs can find most everything that they need to outfit their vessel on Crossroads. In fact, if they have made a good impression on the people there, then they might even be able to negotiate discounted prices for foodstuffs and other equipment. What is more, they can probably hire more crew members if necessary, and possibly even make modifications to their ship (something with which Brother Fain can be helpful). 

Once they've made ready, the PCs can take passengers such as Lt. Vanderwald and his men aboard and then set sail for adventure. 

Part 2—More Encounters in Space

The GM can introduce any of the following encounters during the voyage from Crossroads to Tyr, depending on the desires of the players and the needs of the campaign.

A. Void Natives, Part 3

Some time during the crossing between the Asteroid Belt and Tyr, the PCs run into a scouting party of three mi-go that are hunting an oma for use in the process of item creation. Currently they are on its back, having grappled it, and are using their evisceration ability to dismember it. In fact, it has been driven berserk from the pain, and so is likely to lash out at anyone who approaches.

Mi-Go: Refer to page 193 in Bestiary 4 for details.

Oma: Refer to page 209 in Bestiary 4 for details.

The PCs can approach this situation in a number of different ways. They could, of course, always ignore the matter and proceed on their journey. Force, as always, is another option. They could also rely on Diplomacy for convincing the mi-go to desist in their attacks; to that end, treat the mi-go as Unfriendly for the purposes of the check. As always, the GM should assess bonuses or penalties to the check based on good roleplaying, cogent arguments and other factors, such as offering substitute materials for the mi-go to use in their item creation, or some other kind of compensation.

B. The Spacewreck

At another point the PCs encounter a derelict bark, one that at first glance seems to have been abandoned. The truth of the matter is that it has become infested by a cblack pudding, one that has killed all of the crew aboard the vessel and now lurks down in the bilge, waiting for fresh victims.

Refer to the scenario “At a Crossroads” to find deck plans for the bark.

Black Pudding: Refer to page 35 in the Bestiary for details.

There could be some useful items left aboard the bark, provided they're not made of metal or organic material. Clay or stone jars are the most likely to have survived.

C. Restless Spirits

Some time ago, a ship of the Elven Navy defeated a crew of human pirates. Such was the wicked avarice of the pirates, however, that their spirits still remain, seeking a ship to claim as a prize. They take the form of a spectre, the captain, who at some point appears aboard the PCs' ship. Instead of turning into spectres, however, the bodies of those who are slain by it become animated by other spirits, rising as wights to aid their captain in battle.

Spectre: Refer to page 256 in the Bestiary for details.

Wights: Refer to page 276 in the Bestiary for details.

While this encounter doesn't yield any treasure for the PCs, it can be used to introduce new plot hooks, perhaps in the form of a cryptic clue to a lost treasure that the spectral captain mutters as his last words before dissipating.

D. Out of Control, Again

During the journey, watchful PCs or other crew members might notice that a ship is following them across the void. Those who succeed at DC 20 Perception or Knowledge (sailor) checks can recognize it as the Redoubtable, Captain Axelrod's ravid-powered dhow. While this might at first seem a happy coincidence, the truth is revealed when the gnome's ship steers straight for that of the PCs, speeding in to make a ram attack.

Axelrod is currently affected by Nora the Succubus's dominate person ability; he is joined by a medusa, one who is allied with the demon. She has turned a number of unfortunate victims to stone, and he has animated them using the ravid.

Captain Axelrod: Refer to the scenario “Among the Stars” for details.

Ravid: Refer to the scenario “Among the Stars” for details.

Medusa: Refer to page 14 in the Bestiary for details.

Animated Statues: Refer to page 201 in the Bestiary for details.

This should make for a challenging battle, and one in which the PCs must use discretion. After all, Axelrod is a good, if foolish, gnome, and the animated statues are innocent people, too.

The medusa carries a cold iron dagger and wears a headband of alluring charisma +2. Some of the petrified, animated people might also possess valuables or other items of interest, too—provided, of course, that the PCs can somehow restore them to flesh and blood.

E. Riddles in the Black

As the PCs approach Tyr, they encounter a djinni named Mahmud. He has just been visiting the jann on that world, and, while there, they presented him with a riddle that he has been unable to solve. Mahmud appears at the bow of the PCs' vessel, bows and introduces himself, explaining the reason for his visit. He offers to provide food and drink, if the PCs can solve the riddle.

Question: I serve two masters, one who never blinks and another who is very slow to do so.

They do not always agree with each other, but I am strongest when they stand together.

Who are they and what am I?

Answer: I am the tide, and they are the sun and moon.

Mahmud is true to his word, using his spell-like abilities to create food and wine for the whole crew. He also creates a small wooden statue of an eagle, a token that the PCs can share with the jann to show that they have earned his friendship.

Part 3—The Cold Red Desert Planet

Note as usual that, depending on the solar system in which the particular GM's campaign is taking place, some of these details will change.

When the PCs arrive on the cold red desert world, one word best summarizes what they find: desolation. While this landscape is relatively comfortable by the standards of most other planets in the solar system, it certainly isn't Homeworld. Rust-colored dunes stretch as far as the eye can see, and what little air there is to breathe is painfully cold. In game terms, treat this like “severe cold or exposure” as detailed on page 442 of the core rulebook.

Based on the information from the Constant's logbook, the PCs can find a place to land in the middle of the desert, as indicated on the following map; details for the areas indicated by letters are provided below.

 A. Tunnel Entrance

This location corresponds with the landing area, at the base of a volcano, as described in the journal from the ship Constant. From here, a DC 15 Survival check lets the PCs to find tracks left by the expedition, leading toward the tunnel entrance (Area C).

B. Open Plains

Although this cold red desert planet isn't exactly filled with life, there are some tough and dangerous creatures inhabiting it. Such is the case with a remorhaz that burrows in the red sand. The PCs should make Perception checks opposed to its stealth effort, although it receives a +5 circumstance bonus. It erupts from the ground and attacks until reduced to one quarter of its hit points, at which point it flees.

Remorhaz: Refer to page 233 in the Bestiary for stats.

C. Jann Camp and Tunnel Entrance

Following that attack, a pair of Jann visit the party. They live in the area, and have occupied this land for generations. That is why they know the legends about how the troglodytes once ruled here, but fell into barbarity long ago. They watched as the people of the Royal Interplanetary Company explored the ruins but were forced to flee, and now they wish to know about the PCs' intentions. For that reason they approach openly and hail the newcomers. Then they introduce themselves as Akeem and Zobeida, and offer to share food and drink with them. Akeem then produces an expedition pavilion, which he sets up to provide shelter and concealment.

Jann: Refer to page 141 in the Bestiary for stats.

This scene should present an opportunity for some roleplaying, and provide some information to the PCs. After sharing food and drink with the PCs, they begin the conversation. The Jann know the following details:

• The troglodytes once possessed a civilization that would rival any in the solar system, but their obsession with demon worship led their decline into barbarity.
• For many years, the troglodytes have done little more than linger in their ziggurat, hoarding their secrets but doing little with them.
• Recently, however, a cog—matching the description of the Constant—made landfall, and a party of explorers disembarked from it.
• The jann have been tasked with watching the place. In addition to demonic lore, it is believed that the troglodytes once experimented with powerful elemental magic. They're not sure what all that entailed, but it's enough of a concern that some of the royal genies have asked them to monitor what happens here.
• To that end, they warned the newcomers, but those humans failed to heed their warnings and ventured into the tunnels. Eventually they were forced to flee, boarding their aethership and flying away.
• If the PCs' intentions are good—that is, if they don't intend to unleash a plague of demons on the solar system, or to obtain magic that can be used to summon and bind elemental creatures—then the jann agree to led them proceed.
• Additionally, if they need to do so, then the PCs are welcome to return to the expedition pavilion to rest and recover.

Once they've had enough conversation, the jann invite the PCs to stay the night if they wish, or let them go on their way—assuming, of course, that the PCs win their trust. The GM may want to handle this purely through roleplaying, or could call for a DC 20 Diplomacy check (with the usual bonuses and penalties applied) and perhaps with Sense Motive checks for the jann.

Should the PCs choose not to be diplomatic, or have wicked intentions that are revealed, then the jann might decide to attack them or even to flee the scene to seek more help from their genie superiors. In that case, they could develop into an ongoing problem for the PCs, both as they finish this scenario and further in the future.

 Once the PCs head into the underground tunnel, proceed in the next section. 

Part 4—Into the Tunnels

This scenario does not provide a complete map of the tunnel system beneath Tyr. Rather, a few smaller maps for specific locations are provided, for use with specific creature encounters. The PCs should make a series of DC 15 Survival checks in order to follow the trail left by the party of R.I.C. explorers. 

Cave Entrance

On one side of the hill, behind a tumble of loose boulders and smaller rocks, is the entrance to the tunnel network. It is also the lair for a pair of cytillipedes, which use their cytillesh flash abilities before moving forward to attack.

Cytillipedes: Refer to page 65 in Bestiary 5 for details. 

Chasm

This rope bridge was crafted by the troglodytes centuries ago to span a gorge some hundred feet deep (2). Now it is home to a lone chaugrak, a creature so corrupted by fiendish influence that it has been exiled to the tunnels. Note that the ceiling in this chamber is only twenty feet higher than the level of the rope bridge.

Chaugrak: Refer to page 65 in Bestiary 5 for details. 

The Web

Columns of stone run from floor to ceiling in this long, narrow passage. It is now home to a hive of shriezyxes, which have spun webs across many of the resulting gaps. They now wait inside this giant nest, watching for prey and ready to attack.

Shriezyxes: Refer to page 244 in Bestiary 4 for details.

Piled in the corner near the exit door are a number of items taken from slain R.I.C. explorers, including a lockbox holding 100 cp, sp, gp and pp; a vial of stone salve; and a rope of climbing. 

Underground Lake

At this low point, the tunnel has become flooded with cold, murky water. It is home to a chuul.

Chuul: Refer to page 46 in the Bestiary for details.

The ceiling here is only ten feet above the water. There is a taller, dry cavern in the middle of the passage, in which the PCs can find the remains of an R.I.C. explorer, which still wears rhino hide armor. 

Huge Cavern

After a time the tunnels open up into a huge cavern, with a ceiling 150 feet in the air. Two separate tunnels lead into this chamber from the tunnel network. Additionally, there are two side passages—one that opens into a larger freshwater well, and the other that leads to the troglodytes' cess pit. The cavern is pitch dark, so barring magical means the PCs likely only gain a glimpse of its size. 

Standing in the middle of the chamber is a huge ziggurat; this is, of course, the PCs' objective. Given that, along with the fact that the air has grown steadily warmer as the PCs have moved further underground, means that they probably can and need to rest. Even so, the GM might want to inflict an encounter on them during that time, such as with a patrol of troglodytes mounted on monitor lizards.  

 

Part 5—The Ziggurat

Refer to the appropriate map for the following area descriptions. 

1. Exterior Doors

These stone slabs are not locked, but are very heavy and have no exterior features. For that reason, it takes the use of magic (such as a knock spell) or the combination of a DC 20 Disable Device check along with a DC 25 Strength effort to open. Failing that, the doors have hardness 8 and 60 hit points.

2. Entry

Double doors provide access to these areas, as well as to the rest of the structure. Although one might expect them to be choked with cobwebs and dust, they are in fact clean.

3. Hallway

This passage winds throughout the structure. The ceiling here, as in the other rooms, is ten feet high. The doors are made of stout wood and not locked unless otherwise noted; in those cases, they have hardness 5 and 20 hit points, requiring a DC 20 Disable Device check to open or a DC 25 Strength check to force.

4. Privy

Each of these chambers contains the expected bench with a whole in the middle of it.

5. Junior Acolytes' Quarters

Each of these rooms is furnished with a bed, a desk and chair, and a small chest. At the GM's discretion, the PCs could find small items of value among mundane personal items.

Troglodyte junior acolytes: See below for stats.

6. Senior Acolytes' Quarters

In addition to the furnishings that the junior acolytes have, these rooms also boast large wardrobes for ritual clothing.

Troglodyte senior acolytes: See below for stats.

7. Dining Hall

Long wooden tables with benches fill two sides of this room; the smells from years of food—stuff that's not appealing to anyone but troglodytes—lingers thick in the air.

8. Guard Barracks

Simple beds line the walls of these rooms; they have footlockers underneath them. At any given time, four troglodytes are likely to be found here, sleeping—unless, of course, they've been awakened by the PCs' activities.

Troglodytes: Refer to page 267 in the Bestiary.

9. Storage Room

Shelves line the walls of this room; they are filled with all manner of items necessary for keeping the temple running, including candles, linens, spare writing materials, various kinds of tools and the like. At the GM's discretion, the PCs might be able to find useful items here.

10. Kitchen

Two broad cooking hearths dominate one wall of this room, making sure that it is always warm in here. There are numerous tables used for preparing food, and various barrels line the wall opposite the hearths.

11. Pantry

The walls of this room are also lined with shelves, but they contain all manner of foodstuffs: bottles of wine, cloth-wrapped cheeses, loaves of bread, jars of oil, boxes of spices and the like. Hanks of meat hang by hooks from the ceiling; a DC 15 Survival or Heal check reveals that they are taken from some type of humanoid creature.

Troglodyte Junior Acolyte CR 2 XP 600 Various troglodyte cleric 1 CE medium humanoid (reptilian) Init -1; Senses Perception +1; Darkvision 90 ft. DEFENSE AC 19, touch 9, flat-footed 19 (-1 Dex, +4 armor, +6 natural) hp 19 (3d8+6) Fort +9, Ref -1, Will +3 Resist None OFFENSE Spd 30 ft. Melee Falchion +2 (2d4+1) Ranged Light crossbow +0 (1d8) Special Attacks None STATISTICS Str 12, Dex 9, Con 14, Int 8, Wis 13, Cha 11 Base Atk +1; CMB +2; CMD 11 Feats Great Fortitude Skills Knowledge (religion) +3, Stealth +5 (+8 in rocky areas) Languages Draconic SQ Aura, channel energy 1d6, domains (madness and trickery), orisons Combat Gear Chain shirt, light crossbow, falchion, silver holy symbol Spells per Day: 3/2+1 Spells Known: Create water, detect magic, purify food and drink; cause fear, doom, lesser confusion These troglodytes have begun to taste the power that comes from dedication to Lamashtu, and as such are utterly obedient to Chira'neeth. They fight ruthlessly and unceasingly.

Troglodyte Senior Acolyte CR 4 XP 1200 Various troglodyte cleric 3 CE medium humanoid (reptilian) Init -1; Senses Perception +2; Darkvision 90 ft. DEFENSE AC 19, touch 9, flat-footed 19 (-1 Dex, +4 armor, +6 natural) hp 32 (5d8+10) Fort +10, Ref +0, Will +5 Resist None OFFENSE Spd 30 ft. Melee Falchion +4 (2d4+1) Ranged Light crossbow +2 (1d8) Special Attacks None STATISTICS Str 12, Dex 9, Con 14, Int 8, Wis 14, Cha 11 Base Atk +3; CMB +4; CMD 13 Feats Extra Channel, Great Fortitude Skills Knowledge (religion) +5, Stealth +5 (+8 in rocky areas) Languages Draconic SQ Aura, channel energy 2d6, domains (madness and trickery), orisons Combat Gear Chain shirt, light crossbow, falchion, silver holy symbol Spells per Day: 4/3+1/2+1 Spells Known: Create water, detect magic, purify food and drink, stabilize; bane, cause fear, doom, lesser confusion; hold person, invisibility, spiritual weapon The senior cleric are much like their junior fellows, only more so.

12. Cook's Quarters

When he's not in the kitchen, the cook can be found here. The room is furnished in the same manner as those occupied by the senior acolytes.

13. Cells

Each of these bare stone rooms has four sets of shackles for prisoners. Two of them are filled with the seven remaining prisoners taken from the Constant, who are being kept alive only to serve as food. Once cell is empty, while another is home to a mohrg.

Mohrg: Refer to page 208 in the Bestiary.

14. Torture Chamber

A broad table, one with shackles mounted to its four corners, dominates the center of this room. There are fresh bloodstains on it, since the troglodytes have been torturing their prisoners to determine what the R.I.C. knows about them. Shelves on the wall hold various wicked implements, such as tongs, hot pokers, club and knives, etc.

Chira'neeth, High Priest of Lamashtu CR 10 XP 9600 Male troglodyte cleric 9 CE medium humanoid (reptilian) Init -1; Senses Perception +4; Darkvision 90 ft. DEFENSE AC 23, touch 11, flat-footed 23 (-1 Dex, +6 armor, +6 natural, +2 deflection) hp 71 (11d8+22) Fort +15, Ref +6, Will +14 Resist None OFFENSE Spd 30 ft. Melee Falchion +12/+7 (2d4+3) Ranged Light crossbow +8 (1d8+2) Special Attacks None STATISTICS Str 12, Dex 9, Con 14, Int 8, Wis 18, Cha 13 Base Atk +7/+2; CMB +8; CMD 17 Feats Extra Channel, Great Fortitude, Iron Will, Lightning Reflexes, Selective Channel Skills Knowledge (religion) +11, Stealth +5 (+8 in rocky areas) Languages Draconic SQ Aura, channel energy 5d6, domains (madness and trickery), orisons Combat Gear Chain shirt +2, light crossbow +1, falchion +2, silver holy symbol, cloak of resistance +2, ring of protection +2, incense of meditation, set of numbered keys (see the description in area 7, below, for details) Spells per Day: 4/5+1/5+1/4+1/3+1/1+1 Spells Known: Create water, detect magic, purify food and drink, stabilize; bane, bless, cause fear, doom, lesser confusion, shield of faith; bear's endurance, hold person, invisibility, owl's wisdom, silence, spiritual weapon; create food and drink, dispel magic, prayer, rage, searing light; confusion, freedom of movement, sending, unholy blight; flame strike, nightmare Chira'neeth, the High Priest of Lamashtu, sees himself as the savior of the troglodyte race. Through dedication to that foul goddess and an alliance with her demon servitors, he sees himself leading his people out from the shadows of ignorance and barbarity, and helping them reestablish an empire on this cold desert planet. For that reason, he is unwavering in his faith and unyielding in battle.

15. Library

Of all the rooms on the building's lower level, this one should be of the greatest interest to the PCs. The walls here, too are line with shelves, but these contain books, scrolls and tablets. Between the shelves, carved into the outside pillar, is a bas relief depicting Lamashtu in all her terrible glory.

Various tomes and scrolls in here record the troglodyes' history, along with the lore that they gathered in studying the solar system. The GM can use it to introduce any number of potential plot points, including the following.

• The troglodytes once had a might civilization, but they fell into ruin after earning the enmity of the gods.
• The reason for that enmity is an allegiance they struck with a race known as formians, said to inhabit the next planet out from this one in the solar system.
• The formians were insect-like creatures bent on conquering all of the other worlds, including those inhabited by still primitive humanoids. This was “before any elf drew a bowstring or any dwarf hammered on stone.”
• Although the troglodytes were reduced to barbarity, the formians suffered a worse fate; they were “destroyed in a cataclysm.”
• Chira'neeth sees himself as the savior of the troglodytes, one who will lead them back to greatness in service to his terrible mistress.

There are also texts regarding various types of demons and the worship of Lamasthu; they grant +2 equipment bonuses to Knowledge (religion) or (the planes) checks made regarding those topics. Note, of course, that all of these texts are written in draconic. 

Finally, a DC 25 Perception check or the use of magic reveals a secret door in the ceiling of the room; it can be triggered by pressing both eyes in the bas relief of Lamashtu. Doing thus releases a staircase that descends from the ceiling, providing a means of ascent.

16. High Priest's Quarters

This is where Chira'neeth resides; the room is no fancier than those inhabited by his senior acolytes. Note that, because this room is adjacent to the library, the troglodyte cleric has a chance of overhearing any activity there—and won't take kindly to it.

17. Chamber of the Elements

In stark contrast to the narrow, cramped hallways of the ziggurat's lower level, this level is seventy feet on a side and wide open. Indeed, the only notable features, outside of the staircase leading up into it in one corner, are four stone tables rather like altars. These contain, from top to bottom in clockwise order: ash, dirt, water and nothing. If the PCs don't recognize it right away, a DC 12 Spellcraft or Knowledge (arcane) check lets them recall that these represent the four elements. In the front of each altar there are also four keyholes that match the keys carried by Chira'neeth.

Element/Shape/Position	Keys
Air (Octahedron, A)	2, 4, 4, 6
Fire (Tetrahedron, B)	2, 6, 8, 12
Earth (Cube, C)	2, 6, 8, 12
Water (Icosahedron, D)	2, 12, 20, 30

The trick for solving this puzzle requires a DC 15 Spellcraft, Knowledge (arcana) or (the planes) check.

That lets characters recall that some ancient philosophers associated each of the elements with a particular polyhedral solid. That is, a tetrahedron (four-sided solid) represented fire, a cube represented earth, an octahedron represented air, and an icosahedron (twenty-sided solid) represented water. 

 The keys, then, refer to the numbers of faces, edges and vertices on those different figures. There are four corresponding keyholes in the front of each altar. Inserting the correct key opens part of the locking mechanism for the secret staircase that leads up to the next level, while inserting the wrong triggers the equivalent of an electricity arc trap (DC 25 Perception check to notice; Disable Device 20; electricity arc for 4d6 damage against targets in a 30-foot line; DC 20 Reflex save for half damage). 

Once all of the keys have been inserted and turned, another secret staircase (DC 25 Perception to notice) descends from the ceiling, providing access to the secret vault above.

 18. Secret Vault

This level is the smallest in the ziggurat, and yet the most amazing. It is dominated by a large orrery, one that details the movements of the system's planets and their moons. The steady sound of a clockwork mechanism fills the room. What is more, a large, iron-bound chest sits in the corner opposite the staircase. To protect this place, a shadow demon resides here, tasked with thwarting anyone who might discover the vault's secrets.

Shadow Demon: Refer to page 67 in the Bestiary.

For its part, the demon uses its magic jar ability to possess a PC. Failing that, it tries to follow the PCs while in hiding and thus find an opportunity to frustrate them more in the future.

Characters who examine the orrery can notice—with a DC 10 Perception check—that something seems odd about it; closer inspection—and a DC 15 Knowledge (local) or DC 20 Profession (sailor) check—reveals that this is because it depicts the familiar solar system, but that there's an extra planet represented. Its orbit is just beyond that of the cold red desert planet, and inside that of the massive gas giant. This should strike the PCs as quite strange, although it may occur to them that this position matches that of the asteroid belt. 

Finally, in the chest the PCs can find a collection of clay tablets engraved with an ancient version of draconic. These include tales of the alliance between the formians and the troglodytes, as were detailed previously in the texts from the library, but there's more detail here. The PCs can learn the following details.

• The formian hiveworld was destroyed with a relic known as the Godsharp, a device created by a race of immortal beings known as the azata.
• The azata crafted the Godsharp in order to protect fledgling humanoid races on Homeworld from the predations of the formians.
• Said formians are insect-like creatures that care about nothing more than obeying their queen's commands, which usually involve conquering other worlds and their inhabitants.
• After they witnessed the destruction caused by the Godsharp, however, the azata swore that it would never be wielded again, and hid it away in some unreachable location.
• Through communing with Lamashtu, Chira'neeth has concluded that the spirits of the formians who inhabited the destroyed hiveworld might know where the device was hidden, and someone could learn it from them—provided one knew how to speak with them, of course.

These details provide the PCs with their first glimpse into the true depth of the plot undertaken by the demons and their minions, giving them an opportunity to do something about it. 

In addition to the tablets, the chest contains the troglodytes' treasury, including 1681 gold pieces and 2941 silver pieces (all of an unfamiliar and apparently old coinage), along with five emeralds (1000 gp each).

Development

The PCs can approach the ziggurat and its inhabitants in a number of different ways. While they might want to sweep through the place and eliminate all who are within it, that should prove a daunting challenge. During an all-out battle, more and more troglodytes can appear from their living quarters, with the warriors in the front ranks and the clerics supporting them from behind, until the PCs are overwhelmed. A better tactic is to use stealth for as long as possible, learning more about the ziggurat and then staging short raids—especially if the PCs have access to invisibility and teleport spells. In that case, however, Chira'neeth and his acolytes use their magic to try and find those who've invaded their temple. 

Depending on how the battle against the oni and ogre pirates went during the voyage to this planet, the PCs might find him waiting nearby, hoping to take revenge against them as well as to claim whatever spoils they've taken from inside the ziggurat.

Conclusion

By the end of this scenario, the PCs should have gained a better idea of the enemy they're facing, along with a hint of that enemy's purpose. Armed with that information, along with rescued prisoners, a likely option for them is returning to Crossroads. There are machinations underway of which they're not aware, however, and for them the real trouble is only beginning. 

Appendix—Solar System Map

Presented here is an example of the information that the PCs could find via the orrery in the ziggurat.