West of Constantinople, summer 946.
Aelia, an orphan girl has a secret – she is the daughter of Saint Demetrios. When Patriarch Theophylaktos learns about Aelia's secret, he confines her to a convent and covertly uses her as his personal holy medium. Aelia is initially overawed by the opulence of the Church leaders and the imperial family, but when the patriarch tattoos the Chi-Rho symbol onto her foot, she realises that she is just the patriarch's possession.
Although Aelia suffers rape by Prince Romanos, it is only when the patriarch tattoos her newly-born son Alexandros that she is roused into open defiance. Aelia decides to reveal her secret to her close friend Kassia, and rely on her kindness to raise him beyond the patriarch’s reach.
Kassia and her husband Andreas meet the benevolent Ambassador Liudprand on the road, and he offers them a home and work in the West.
Theophylaktos’s downfall begins when Aelia is kidnapped. Unable to raise the ransom and fearful of divine vengeance, Theophylaktos agrees to accept gems from his nephew, Michael, and swears an oath of loyalty. Aelia though is rescued by monks loyal to Demetrios, and the patriarch is led to believe that Aelia has been sold to Arab traders. Michael, believing he is the rightful heir to the throne, calls upon the support of Theophylaktos and forms a rebel army.
Alexandros has vowed to find his mother and returns to settle in Constantinople with Kassia, Andreas. He locates the mortally wounded Theophylaktos on the battlefield and learns that Aelia may attend Saint Demetrios’ shrine on his feast day.
Aelia and Alexandros are reunited at the shrine after a monk notices the tattoo on Alexandros’ foot. Kassia and Aelia establish the Refuge of Saint Demetrios in a property bequeathed by Liudprand to help young women in unfortunate circumstances.