Jupiter - the old name for the King of the Gods. It is surrounded by moons and drenched in meaning. Not only does every one of the eighty eight surviving moons have a name, it has a legend; a story of one of Zeus' many lovers, still orbiting her celestial form. And it is at war.

Not a war as any of the Tellurians might recognize it, but one that makes an instinctive sense to Dyssia. This is a pretend war. Across the surface of many moons robotic crawlers move, recycling fields of debris and setting up factories, command nodes and fortresses. They orbit clockwise, because on the other side of the moons is a constantly shifting front line as heroic individuals tear through endless mechanical hordes. Your lenses cannot make out specifics at this distance, other than that it is few against many.

There is a network of long distance beacons surrounding the warzone with a rosetta stone worth of warning messages. The scribes and analysts aboard the Plousios make extremely rapid work decoding this archaic series of languages, and once a Plover is dispatched to investigate they find a series of large synthpaper instruction manuals attached to the outside of the beacons. Bringing one back and working through the language sequences, a message is uncovered:

THIS IS NOT A PLACE OF HONOUR.
NO HIGHLY ESTEEMED DEED IS COMMEMORATED HERE. 
THERE ARE NO DANGERS THAT MIGHT SPREAD, AND NO TREASURES WORTH SEIZING. 
THIS IS A MEDICAL FACILITY AND THE PEOPLE HERE ARE ILL.
THE SICKNESS IS OF THE MIND. 
THESE PEOPLE REQUIRE AN ENEMY TO FIGHT AGAINST.
IF AN ENEMY IS NOT PROVIDED, THEY WILL INVENT ONE.
WE OBSERVE THESE PEOPLE CLOSELY.
SOME RECOVER FROM THEIR ILLNESS AND ARE RETURNED TO SOCIETY.

From there, the text goes into details about the specifics of the game. It is a dizzyingly complicated situation, overseen by a powerful digital intelligence. The open war is only a small part of it; there is also a transcendentally complex civilian side based around investigation and paranoia. Symbolism is encoded everywhere, chains of meanings that reveal reptilian infiltrators shape-shifted into human form. Some are given powerful combat armour and placed in a hostile alien environment behind Enemy lines where their full attention can be given to survival, others train and lead swarms of perfectly obedient robots to expand their territory and claim further resources, others act as inquisitors searching for the wicked infiltrators amongst the civilian population (which is itself 99% comprised of infiltrators). 

There is a second layer to the game. Though the Enemy is designed to appear faceless and mindless, if carefully observed an observer might notice clues that they are capable of intelligence, kindness, empathy, romance and peace. A patient who pursues these clues and begins to seek rapprochement with the Enemy is placed on a story path where this empathy is validated and developed further. Notably, simply switching binaries - the Enemy is good and Society is bad - is not sufficient to 'win'. An inmate is to develop an appreciation for complexity and nuance before being allowed to graduate.

In all, the disease the moons of Jupiter seem to be attempting to cure is [i]evil[/i]. Across eighty eight moons, paranoia, greed and violence is controlled and channeled while subtle lessons about empathy and virtue are taught to those with ears to listen. It is not quite the Kingdom of Hades, or the Thousand Hells of ancient folklore, but it represents a genuine effort from the people of the Solar System to build one of their own. And...

There is a shadow there. A chill. A memory of home. Those of you born of the Underworld instinctively recognize that this is a temple and a prayer, and for the first time since you came into the burning hot summer of this galaxy you can feel the touch of [i]home[/i]. This edifice has made a link with the Underworld and driven back the eternal blessing of Demeter's summer. Beneath the gaze of Jupiter any death will be final, sending your souls to the underworld rather than transfigured into vibrant new life. You did not realize how hot the stars had been until you stepped into this cool shade.