Lucius is a young Centurion in the time of Hadrian, serving at Trimontium, modern-day Melrose in southern Scotland. Trista is a Roman patrician girl, living in Gaul. She is orphaned and becomes a vagrant when her parents are killed by traitors plotting to overthrow the emperor. Following the death of his wife, Lucius becomes an imperial agent, operating beyond the borders of the Empire as a trader, seeking signs of invasion. He meets Trista who is under threat of assassination. The story follows their flight across Gaul, pursued by evil forces, to the German forests in a race to avert...

Xiang Li is a cultured, rational Chinese Mandarin, Governor of Xinjiang Province. He sees a sign in the skies and falls under a compulsion to travel to the west in the depth of winter. Nothing is clear but that he must hurry. His journey takes him through the snow-choked passes of the Tian Shan mountains and the searing heat of the Syrian Desert, through ambush by evil tribesmen and the deadly court of King Herod, while ahead of him rises a light in the night sky...