Nothing ever changes in Ravnica. For countless millennia, cities have covered the entire plane. Eventually, they ran together into one vast megalopolis -- a patchwork of grand halls, decrepit slums, ancient ruins, and layer upon layer of stonework structures. The world of Ravnica is an ecumenopolis, a vast city that covers the entire surface of its planet, and is home to a diverse assortment of sentient races. For ten thousand years, there has been a power struggle between the ten Guilds of Ravnica, political factions that each represent a combination of two of Magic's five colors. Ten millennia ago, the Guildpact was signed by the paruns, ending active warfare between them and ushering in an era of peace. But now, on the eve of the celebrations of the accord's ten thousandth anniversary, a sinister force threatens the survival of that peace.