It is December 1033, and in Constantinople, the capital of the Eastern Roman Empire, the Christian community is terrified by apocalyptic visions, for exactly 1,000 years have passed since Christ's Resurrection. Onto this stage arrives Prince Harald Hardrada, the exiled heir to the Norwegian throne. Caught up in the cross-currents of palace intrigue, secret sects and the search for religious relics, Harald recognizes a constantly-recurring figure: St Helen, the woman who converted the Roman Empire to Christianity through her son Constantine, seven centuries earlier. But what is her hidden legacy? Aided by a mysterious girl, Harald's mission is to uncover the truth, and the survival of the Empire, his very life and that of his friends, will depend on what he finds. They must make haste, as they are not the only ones keen to get their hands on St Helen's hidden heritage.