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, political factions that each represent a combination of two of Magic's five colours. Ten millennia ago, the Guildpact was signed by the leaders of the ten factions, ending active warfare between them and ushering in an era of peace. But now, a sinister force threatens the survival of that peace.
After leaving Origin Earth, Mark and Luke travelled to a world they believed to be Ravnica and arrived in a church that was potentially Orzhovian. They didn't spend much time investigating, as they were needed to quell a battle between Liliana Vess and Garruk Wildspeaker outside.