Runnik Gorestead was your trusted ally, a barbarian dwarf whose love for his hurling axes and meads was matched by his disdain for new-fangled firearms and urbanization. He had been with you for over a decade of adventures across the face of the Earth and all throughout the vast city-state of Ysidra. Your home in recent years has been here in the world's greatest city -- a harrowed and haunted city with multiple millions of inhabitants, densely inhabited, built and rebuilt across the millenia atop countless ancient ruins. In its Government District stand vast outsider-constructed megastructures: monuments to alien super-human egos of godlike beings who once aspired to rule this plane.
Now your friend Runnik had suddenly gone missing, under suspicious circumstances. As he had saved your life, and vice-a-versa, many times, you had to find him and rescue him if need be.
A few days into your investigation, a voice reached you by a magical sending.
"I believe we share a common goal. I have information about the individual you seek. Meet me at midnight in the Dancing Lancer tavern."
The Dancing Lancer was a tavern in the Harbor District that you and your trusted allies could reach by midnight of the day you received the message.
At the appointed time, you arrived at the bustling tavern. It was in a wealthy neighborhood of the Harbor District, and a substantial fleet of foreign merchants had arrived in port. But in bustling crowd you met a man in an eyeless, red leather mask. He motioned for your to sit down in a side booth, before speaking in a hushed voice that sounded as though it might be disguised with magic.
"I apologize for my rudeness in contacting you so suddenly and briefly, and thank you for meeting me here. I cannot tell you my name, but I am one of the PeersThe Peers are a group of nobles, artistocrats, high ranking guild members, and clergy who collectively rule the city. working anonymously to combat various evils afflicting Ysidra. What is doubtlessly more important to you than my name is how I can help you.
"In recent months, I have been investigating the disappearance of a high-ranking government agent code-named named Osprey. I have discovered a series of similar disappearances throughout the Ysidran Republic and its affiliated islands, all of which occurred under similar circumstances. In each case, the missing person was last seen with an attractive stranger and appeared to be rapt with the new acquaintance's beauty and charm. Reports in most cases place the missing individual in the company of the same stranger, heading into a Government District mega-tower, a place called the Somal Observatory. Your missing friend is among those whose disappearance matches this pattern.
"Our divinations have located several of those who vanished, as now being located upon the moon.
"Long have reports spoken of a demon-tainted jungle on the surface of the moon—what we on Earth see as the Moonscar. It is there that I believe those abducted have been taken, though for what sinister succubus plot I know not. Few have the means to venture into such a realm, which is why I am here now, with you. There is little I can offer you beyond pointing you in what I hope is the right direction. Yet, if you can investigate the Somal Observatory, and find how that lets one travel to the moon, and there retrieve not only my missing agent and your friend, but any other captives of the demons there, then my faith in you will have been well-placed.
"Now -- Whatever plan the Moonscar's Insatiable Queen and her servants have in the works, it has sped up drastically, and I fear for us all should they not be stopped."
You geared up and investigated for several days.
The Somal Observatory was a tower, over two thousand feet tall, built in the central core of Ysidra. It was thousands of years old; it had been raised by arcane magic by beings from alternate realities, who for some time had contended for rulership of this Earth -- only to eventually abandon that project due to prolonged and destructive in-fighting orchestrated by the subtle manipulation of history's greatest diviner, the Harrower Queen, and immortal lich.
The bottom ten or so stories of the Somal Observatory were simply houses and offices for people who lived and worked in the Government districts. But above that, the tower walls rose up, and up, and up ... to stupendous, dizzying, soaring heights.
The tower was mostly hollow, but for struts and cross-beams. The inside was lit my sunlight through many crystalline windows. There were stairs that climbed upwards, but gradually rather then resembling worked stone, they morphed and became more rounded and organic-looking. For the tower had been grown, by magic, and was still a living artifact not a thing made by mortal hands. The spacing of the stairs grew more and more irregular, until about 300' upwards, only the most expert of climbers could proceed.
You were all expert adventurers: you all had means of flight (*). And, so (watched by hundreds of curious gawkers) you simply flew upwards through this vast building. Its extreme size reflected the bloated egos and grandiose dreams of alien minds who once thought to rule this world as they reigned in extraplanar heavens and hells. Their infighting had been inspired and shepherded by the ever-devious Harrower Queen: who ages ago was Earth's savior -- though now she is the Harrowed City's secret occult ruler. But this is not her story.
Atop the tower you found grand crystal observatory dome, with many telescopes and mechanisms for watching the stars, planets, moon, and other such celestial objects. About half of this area was in ruins, but about half cleaned and in working order, tended by golems. The golems served a mad old gnome you soon met, named Gavriel Glittercombe, who operated what he described as the Great Telescope. It not only brought the images of distant places close, but it bent space itself allowing transit to what places it could view and bring into focus.
Gavriel Glittercombe confessed his delight in receiving many new recent clients, who were paying him well so that he could rebuild his golems and parts of his observatory.
Pressing him on the details, it became clear that he, his telescope, and his golems were enabling the passage of succubi, and their beguiled partners, and others to transit to and from the moon.
But the delicacy and complexity of the equipment and the variety and diversity of his golem forces was so great that you deemed it imprudent to engage in direct conflict to overpower Gavriel Glittercombe and seek to control the Somal Observatory for yourselves. But rather pay him to achieve your own transits, for your own rescue services.
One of you went on a preparatory 24 hour scouting expedition. (The Great Telescope took at least 24 hours to recharge, and it required a clear cloudless line of sight to the moon to function.)
When that mission (while dangerous) was successful, you had learned enough to prepare for your own voyage, and decided there was no time to wait.
You paid Gavriel Glittercombe for your whole group to transit -- and you paid himThese pre-trip preparations cost you 45,000 gp.
But I will not set back your starting wealth because of this. in advance for a return journey, he would be awaiting a signal via a permanent telepathic bond created with his familiar.
Now, you must trust that he is both still alive and honorable enough to respond to it, or you will need some backup way to return from the moon! It is likely that succubi and their captives will still be coming and going: Gavriel Glittercombe never agreed to make your access exclusive.
Your adventure begins, as you enter the Great Telescope's transport circle. Once sent of lenses focus on your group, while main cylinder of the telescope aligns on the distant moon. Gears whir and grind; steam puffs out of the machine, and it glows and vibrates. Then pace-time bends and shifts, and you take your first steps onto the lunar surface, entering the demon-infested jungle of the Moonscar.
(*) Note: All PCs must either have a spell, ability, or item that grants them flight. Purchase one as needed. If you want to save money, you can pool resources and share a magic carpet. You won't be able to rely on flight constantly in this One Shot as it poses special risks, but at this level there are moments where the ability is a presumed must-have.
(**) Note: Spells above 6th level are not available. So transit to and from the moon is not as simple as getting a scroll of interplanetary teleportation. It may require some elaboration construction, rituals, or artifacts to get back if Gavriel Glittercombe proves unreliable.