C rdoba, 976 CE. The caliph is twelve years old. Power belongs to his chamberlain.
And in the restricted stacks of the palace library, a scholar has been found dead in a locked room - dry, unmarked, impossible.
Diego ibn Anselm is a translator. A Mozarab. A man who belongs to no single faith and speaks every language. When the chamberlain asks him to investigate, Diego expects a murder.
What he finds is older. A network born in 718 CE, when seven people from three faiths decided to protect something fragile and extraordinary: the city they shared. A founding document hidden in three pieces across three communities. And someone who will kill to possess it entirely.
The city of C rdoba is the most advanced city in the Western world. It is also the most dangerous thing Diego has ever been asked to save.
"The thread holds. Until someone cuts it."