Constantinople, 1179. Princess Agnes of France is 13 when she marries the heir to Byzantium, an empire unmatched in wealth and power. But once she sets foot in the Queen of Cities, a decadent world where dazzling luxury masks unspeakable cruelty, she realises that her husband is a deluded mother's boy with mighty enemies and treacherous allies. As emperors rise and fall, Agnes learns to play the City's game – until she falls for a handsome rebel and finds that love is the most perilous game of all. Only when crusading knights from her homeland attack the City, does she finally understand what is truly worth fighting for.