This story is set in the late seventh and early eighth centuries and focuses on the life of a young Saxon, Alric, born in the year 775 at Wearmouth in Northumbria. He has a twin sister, Hilda. His parents plan for them to take vows. Alric will enter the monastery at Wearmouth, while Hilda will enter the convent to the south, at Whitby. All is well until Wearmouth is the focus of an attack by sea raiders (now known as Vikings) from Scandinavia who appeared out of the morning mists, killing and pillaging without remorse. In Alric's sixteenth year they return to Wearmouth, and Alric is captured. He is taken from his home as a captive bound for a fjord in what is now modern Norway. A severe storm causes the ship to be beached, and the raiders suffer the same fate as their victims, but at the hands of a party of Mesopotamian soldiers. Through the courtesy of the commander, Alric eventually ends up in Baghdad, where Harun al-Rashid (Aaron the Just) is the Caliph and at the time the tales of A Thousand and One Arabian Nights were being told by the Caliph's wife, Scheherazade. Alric is apprenticed to an alchemist with medical knowledge, where his role is to pursue science and develop drugs and other chemicals that help the Caliph's cause. During this time, Alric becomes a valuable member of the Caliph's inner circle and becomes familiar with the inner workings of the House of Light, comprising the royal palace and the Great Library. As a result of his work, he is able to rise from the position of captive to apprentice to a status in which he is able to make contributions to science and medicine. However, he becomes embroiled in the politics of the palace and a plot to assassinate the Caliph. Coupled with this, he discovers a cuneiform tablet that had once been the prized possession of King Nebuchadnezzar and gives him an insight into chemical and medical science. This tablet also contains a prophecy that Alric must fulfill.