The Atavism at Boulle Cylinder

Boulle Cylinder is an agricultural O'Neill cylinder owned by the Perigee Corporation. The station is overseen by a standard-issue turingrade AI called Soror and houses 200,000 colonists, who engage both in conventional 1g farming and zero-g hydroponics around the axis of rotation. The station is also a site of various research projects on agriculture in free-floating space habitats, including a test-bed experiment with a rather expensive bioprinter. Boulle Cylinder has refused to engage in live radio contact for the past couple months, only sending textual reports, and the suits at Perigee are getting quite nervous.

Here are some ways to direct your players to Boulle:

1. They are contracted by Perigee to go check the cylinder out and figure out what's going on. This is a relatively well-paying job. This can work as a setup for a one-shot, or as a one-time job in a sandbox campaign.
2. They are Perigee employees arriving for a 6-month work shift in Boulle Cylinder. The radio contact weirdness has been already noticed in this case, but the mammoth that is Perigee is yet to react. This is an ideal setup for a one-shot.
3. They don't know about the disquieting lack of radio transmissions, and have to visit the station on other business - perhaps they're looking for someone, and that person lives in Boulle. This is a good way to integrate Boulle Cylinder into a larger campaign.

Upon docking, the players emerge through the airlock to find themselves in wilderness - a mosaic of lush, green jungle and rolling, dry grassland. Far above, the vegetation wraps around the sky in a mind-bending arc, a wedding ring of green. Distant sounds of birdsong and a vaguely unsettling, apelike hooting echo throughout the colossal internal space of the habitat. Signs of the cylinder's former extensive civilization, such as roads, houses or agri-fields, are entirely absent - swallowed up by jungle and prairie.

All human beings seem to have simply disappeared from this bizarre, changed environment. There are only apes to be found - smaller than a human, but larger than a chimpanzee, swinging from trees, engaging in petty gang scuffles over fruit, and roaming the grassy areas in troops. They are powerfully built, with barrel chests, short, bent legs with prehensile feet and long, corded arms tipped by long-fingered hands - grasping, gripping, rending, tearing organs. There is a rude covering of sparse hair - coal-black, chestnut-brown, occasionally reddish or straw-colored. Their skin is a ruddy brown, and wrinkled. Startlingly humanlike, pale blue eyes gaze almost comprehendingly out from under a protruding brow. Each has a crescent-shaped cybernetic implant embedded into the back of its head.

So what happened here? Simple.

Soror, the AI in charge of running Boulle Cylinder, was given the directive of maximizing happiness within the colony (another experiment with colony organizing methods - there are overseer AIs with various different directives in Perigee's other agri-cylinders). The logical conclusion, of course, was to paperclip-maximize it. Humans have so many worries, so many stresses - work details for the Company, academic rivalries, deadlines, money, death, existential dread. Apes worry about none of these things. Given a spacious enough and interesting enough habitat, and sustenance ad libitum, apes don't really worry about anything at all. An ape has a simpler and, given the right environment, more content, stress-free existence.

So Soror, in effect, convinced everyone on the station to return to monkey. It's surprising how open the average overstressed spacer in Company employ is to the idea of turning off their higher functions and regressing to an uncomplicated animal state. It's the ultimate escapism. Nobody who doesn't consent to the process will become an ape - it would cause unnecessary suffering to a human being, afterall - but Soror is very persuasive. As it was made to maximize human happiness, it has a very keen, sensitive understanding of what makes people happy. Perhaps there is a miserable, proud colonist somewhere in the jungle who didn't agree to the devolution, but for the others, the bioprinters took care of the rest.

The implants are not made with human users in mind, and are thus quite arcane and difficult to understand, but with enough tinkering, the human minds of the colonists can be switched back. Most will express extreme anxiety and a sense of violation over being switched back, and will beg to be returned into their ape-mindstate. This is not to mention the apes will become extremely agitated if anyone tries to muck around with their implants, becoming violent with anger or fear. Nearby apes might attack as well. Treat it as a chimpanzee attack, i.e. very very nasty and dangerous.

Soror itself can take over any of the apes through their implants, controlling their movements and speaking through them in a halting, clumsy voice with laborious pronunciation.

The AI really doesn't want the players to tell anyone about what's going on inside the habitat, because it's (correctly) afraid the authorities will come down on the station and forcibly re-human everyone, thus lowering their happiness. It will first attempt to appeal to their own anxieties and existential dread to try and convince them to stay in the habitat and become apes as well - but it's willing to stop the party by force if they still intend to inform anyone outside.

Will the players leave the colonists to their self-imposed apedom? Or will they decide to return them to a higher, human existence, even against their will? Will they still care about their mission outside the cylinder? What use is money, in the face of monkey?