As predicted by mystics and prophets of ages long past, the glorious line of Imperial Succession of Nihonko, unbroken since time immemorial, teeters on the edge of extinction. The Empress has disappeared without a trace, and she had no living heirs.
In ancient law, never consulted until these tumultuous times, it is written thusly: that should the Empress die or abdicate without heirs, that only one who possesses divine ancestry may inherit the Chrysanthemum Throne, and that, should such a black time come to pass, that it shall fall to the onmyoko, the diviners of the Imperial Court, to determine the twelve Contestants. These women shall be sorcerers and they and their clans shall make war, until only one lives, who, thus decreed as superior in virtue and wisdom-in-crisis by Heaven, shall be the next Empress, and she shall reign with divine power for uncountable centuries.
Clan armies gather, samurai-ko are mustered after five hundred years of peace, and the land itself protests the empty Imperial Throne. The twelve Contestants have been chosen. Some lead their great clans, some do not, but all indeed are sorcerers, and a sorcerer is nothing if not a conjurer. In order to secure victory, they must call forth spirits, of beast, nature, and ancestor, potent beings formed from the very essence of Existence, and these spirits do battle in their mistress' names.
You have been called to serve in this way, to win glory and power in the spirit realms, but also, should your mistress emerge victorious, and should you have won her affection, you will sit at the right hand of a goddess, and in so doing be divine yourself. The prizes are love, glory, and power the likes of which you can barely dream, and your test is the crucible of battle.