In an exotic ancient land, a foreign stranger's sworn mission of vengeance leads him into the perilous circle of a ruthless Byzantine empress. In the early years of the ninth century, the road home from Jerusalem winds through Constantinople for two Frankish noblemen-warriors. But when an encounter with a young woman running for her life results in the murder of Hagen the White's brother, he vows to find the perpetrators, no matter how highborn or powerful, and take his revenge. His hunt will carry him into the royal circle of the Basileus Irene, a ruthless despot who blinded her own son to force him off the throne. The beautiful and calculating empress is fascinated by this supposed barbarian who has sworn allegiance to the great Charlemagne, and she welcomes him into the imperial court and into the dangerous fires of countless royal conspiracies. Suddenly Hagen must tread carefully through a vipers' nest of plots, lies, and bloodthirsty power plays, for if the stranger trusts the wrong serpent, he will certainly die.