In the year 1260, a great cathedral, the most ambitious ecclesiastical building in all of Christendom, is rising high above the bustling city of Cologne under the supervision of the architect Gerhard Morart. Far below the soaring spires and flying buttresses, a bitter war rages between the archbishop and the city's ruling merchant families – a deadly conflict that claims Morart as the first of its many victims. But there is a witness to the murder of the unfortunate architect, pushed to his death from the cathedral's scaffolding. A cunning, street-smart, politically naive petty thief called "Jacob the Fox" has seen it all – and seeing has made him the target of a relentless and ruthlessly efficient assassin who's been stripped of his humanity by dark, hidden secrets. Ensnared in the strangling vines of a terrifying conspiracy, the Fox must now run for his life. But who – and what – is he running from?