The Jahan campaign is divided into three tiers. Each tier is intended to be a complete sandbox. However, the first and last adventures in each tier are predetermined.
There are two eternal forces of creation and destruction. In Kishar, they were known as Tiamat and Absu. Now they are known as Ormazhd and Ahriman. For eons they struggled, making and unmaking world after world. Eventually, they sought escape from this endless cycle of birth and rebirth. They attempted to channel their destructive energies through proxies: the igigi and the sphinxes. However, the igigi ascended to godhood and slew Abzu and Tiamat in turn. But these primordial entities cannot be truly slain. Slowly, they regrew in strength and presented themselves to the Prophet, who dubbed them Ormazhd and Ahriman. The igigi and sphinxes are dead or de-immortalized. Soon, the two will reach their peak and, without proxies, the world will be destroyed and recreated again.
As they grew in power, they began to manifest in the world, but in pieces, shattered as they had been by the igigis' slaughter. These manifestations are the twelve lesser powers (six for each). They each represent an aspect of their original entity's personality, and only imperfectly understand what is going on.
The Prophet was someone sensitive to the metaphysical transformation occurring. He perceived these creative and destructive forces in a vision and named them Ormazhd and Ahriman. His vision was imperfect and he did not entirely understand what was happening, but he did understand that the two entities would eventually flower into their full personalities and then devour the universe to create it anew. He spread his message, and learned to tap these powers to reintroduce divine magic into the world. Because the forces were weak, his divine powers were small, and his "powers" were derides as chicanery by most. His order was persecuted until centuries after his death, and many of his writings were lost.
The djinn, abandoned by the gods, heard the Prophet's message and felt its intrinsic truth. They converted to the One Religion. One potent djinn sought to resolve the conflict and was most intrigued by the prophecies involving Zurvan, the one entity that would combine both Ormazhd and Ahriman. She took her followers, both mortal and immortal into the desert. She wove fantastic enchantments to hide their presence, and then sought to research a way to create Zurvan.
Unfortunately, he was betrayed. A well-meaning priest let loose a few ill-placed words in a local bazaar. The words were found by an ambitious warlord and his powerful viziers. They, too, were devotees of the true religion, but they followed the destructive path of Ahriman, and most of their magic was dedicated to abjuration. They assaulted the city, seeking the wisdom and items hidden within. A mighty battle raged, with terrible magics being unleashed on the region. The djinn were first set off-balance by the raid, and many of them were banished to far realms or trapped in mundane objects. The djinn had relyied too much on their magical defenses and secrecy to protect them. During this time, the warlord and his viziers collected many magic artifacts and tomes of ancient knowledge.
Then, the djinn regrouped and assaulted the viziers and warlord. The invaders were driven back, and slowly were surrounded. Desperate, the viziers hastily crafted a mighty ritual that banished the entire city. To seal the ritual, they used the warlord's own blood as the key. Only the warlord or one of his descendants could restore the city. The warlord promised his viziers that he would use their magic to raise another, more powerful army, and return to raze the city.
He never did. Instead, he betrayed his own companions. He used the lore and magic to found a great empire, known for its fantastic magic. The key was passed from generation to generation, as was its secret. The Sharif of the Empire had to be careful to whom he passed his seed, for if any of his kin were to enter the desert, the city would reappear, his viziers would know of the betrayal, and the djinn may return.
For centuries, the empire prospered and flourished. But decadence took its toll and now the Empire is in decline. The Sharif is old and faltering. His eldest son is cruel and decadent. But the eldest son has a younger brother. As is customary, one the eldest son married, the younger children were expected to take vows of celibacy and lead the Imperial armies or join the priesthood. But the younger son had fallen in love. The elder brother would not abide it. In family tradition, he sought to have his brother killed. The brother's lover was captured and place din a mirror as part of a trap. The Prince, along with a company of loyal companions rescued the mirror but were unable to free his lover. They fled the capital. The Prince had learned enough of the family secret to believe that the desert held secrets he could use to rescue his love and perhaps even reform his kingdom.
When he and his company entered the desert, the city appeared as if a mirage. He entered the city, and found one of the viziers, still recovering from their restoration. The viziers deduced what had happened and sought to capture the prince to wreak revenge and to solidify the city. The Prince escaped once more, and as he left the city it began to fade. But the prince had seen enough of the city to understand that it did hold great wonders, wonders that could rescue his beloved.
Meanwhile, the king and prince concocted a story about the brother attempting to usurp the throne. Wanted, he took on the guise of a poor adventurer (not far form the truth). He stayed near the city, and realized that the closer he got, the more solid the city became. His blood had power still.
A desert sheikh saw the City of Mirages and claimed it as his own. He then called upon adventuring companies from across the land to come to the desert and explore this city. The shiekh would take his portion of any treasure found, and let the company keep the rest. The prince and his company signed on as adventurers. But the elder brother deduced what had happened and sent his own adventuring company to find and kill the Prince. The PCs are a third company.
Lords of RuinThe party explores the ruins of the city, learning a bit about the origins of the city, and meeting some of the viziers, who need to find and capture the Prince in order to be free. They also meet the other companies, get some treasure, befriend and gain the trust of the Prince (in disguise), and learn more about what is happening in the Empire. The heroic tier ends when the Prince's identity and the Sharif's assassins are exposed, and the party learns the history of the Empire. Also, the Viziers cast a spell to capture the Sharif so as to permanently anchor the city in reality.
Lords of MagicThe Sharif has fled into the desert with the Shiekh, but is contact with the PCs. They must remain in the city to stop the Viziers and to rescue the Sharif, while the son prepares to battle his brother. As the party defeats the viziers, they djinn begin to escape their bonds. The party begins to learn the history of the True Religion. This tier ends with the brother vanquished, the viziers defeated, the genies freed, and the end of the world on the horizon.
Lords of DjinnThe Genie Queen is free and she intends to cast a ritual to destroy Ormazhd and Ahriman. She has fled to the legendary City of Brass. Their friend the Sharif charges them with discovering what happened and then saving the world, by whatever means necessary.