Yimix, City of Many Worlds
Up until thirty-five years ago Yimix was a normal city, populated by good, highly religious people. They worshiped a higher power, an entity of light and good that protected the small city. Yimix had a small standing army, though the soldiers were little more than ornaments or police, due to Yimix’s peaceful nature. Other cities had only good things to say about the citizens of Yimix, calling them good traders and pleasant people.
Thirty-five years ago this all changed, with the coming to power of a new arc mage. The arc mage was surprisingly quiet and introverted, but also very devout. He spoke with the high priest of Yimix’ god, and together the two developed a ritual of great power. Once the ritual was fully designed, the high priest told the citizens of Yimix of what they had developed. Using a Well of Many Worlds, the two had discovered a way to bring the entire city of Yimix to any world they desired, by simply finding it in The Well and expanding its magic throughout the entire metropolis. The high priest and arc mage proposed that they use this ritual to bring Yimix to the plane their god existed on, to their heaven. The proposal was met by overwhelming approval and cheers, and those who did not agree were handsomely compensated to leave Yimix and start a new life elsewhere. Under a full moon the arc mage and high priest began the ritual, which would have succeeded if everything went according to plan. Unfortunately, something went drastically wrong.
A group of adventurers had been hired to counter a plot by an evil sorcerer to open a gateway straight to the hells. The adventurers mistook the arc mage for this sorcerer and believed that this ritual would open a planar rift to the demonic planes instead of to their heaven, tearing apart Yimix in the process. On the night of the ritual they broke in, killed the high priest and the arc mage and destroyed the Well of Many Worlds at the climax of the ritual.
The magic and energy normally trapped in the well spread out across all of Yimix. This did exactly what the two spellcasters had intended, with one major change. Yimix was transported from its current world, but not to heaven. Yimix became completely unanchored in space, shifting from plane of existence to plane of existence every twenty-seven hours and nineteen minutes. The new location is mostly random (and determined by the DM,) however it has been known to fall into some patterns.
Firstly, once every one-hundred and ten “shifts” Yimix returns to its original plane of existence, exactly where it was originally. Secondly, Yimix has been known to fall into what the citizens have dubbed “cycles,” during which it returns to the same world every three shifts. This can last for any number of shifts, but the cycle is broken as soon as Yimix returns home.
Certain rules govern the way Yimix interacts with its new environments. First, all of those trapped in Yimix (those who were within the city walls when it became unanchored in space) are transported back into the city when it shifts if they are outside the city walls. The process is very painful and knocks them out for twelve hours, so all citizens of Yimix make sure to stay within the city walls during the shifts. Secondly, all within the city walls become trapped in Yimix just as though they were inside the city when it became unanchored in space. Thirdly, Yimix cannot take up space that is already occupied by another city or town. Individual creatures that are present when Yimix comes into a plane simply find themselves in the city, on a street or a household. Yimix prefers open areas, planes of wheat or open fields. If necessary, as in the plane of shadow, it can appear in the sky with a large chunk of earth beneath it. Yimix also carries an air pocket and produces its own oxygen, for planes where there is none.
Yimix can serve as a number of plot purposes.
The Mystery of Yimix-The heroes find Yemix and come back at a later date, only to find that it is gone. Eventually they see Yemix return and must discover what happened thirty-five years ago. The heroes may try to find a way to save the city and its citizens.
The Raiders-Yimix no longer produces food or agriculture in mass quantities, due to the many climates it passes through. There is simply not enough sunlight, and often the climates it passes through are too harsh for serious growing of crops. As such, when the citizens need food and cannot trade for it, or fish or hunt enough, they must resort to raiding. The heroes can be hired to find these mysterious raiders, and discover Yimix and its suffering citizens.
The Trapped-The heroes wander into Yimix and stay the night, are overlooked by the citizens due to the enormous number of people living in the city, accidentally become trapped. They must find a way to either escape the city or re-attach it in space, or else be trapped there for all eternity.
The Rescue-Heroes from the plane Yimix was originally on are hired to rescue the adventurers that killed the arc mage and high priest. Those that survived were captured and imprisoned for the last thirty-five years. The citizens of Yemix are justifiably unwilling to release the people they see as being responsible for their current predicament. The heroes must rescue them (note that the adventurers are imprisoned in Yemix as well, and must somehow get out.)