Peter and Siobhan are reunited, as their growing skills can benefit serious crises of the past. For this they are wanted at Lindisfarne when the Vikings attack in AD 796. The Time Road takes them back from today, with a pause to improve their fighting skills with William Sargent, the greatest knight of all, and their bowman ship with an aging Robin Hood. By the time they reach Lindisfarne, the Vikings have killed many of the monks and stolen treasures. The two young warriors travel by Grace OMalleys galleon to Viking land. There they have to fight their way through to a prison where Merriline has been captured. The battles are terrifying, but with their skill to become invisible and their enhanced fighting talents, Peter and Siobhan eventually rescue the great, but not necessarily grateful, wizard. Meantime, the battle between good and evil is heightening up. The next target is the late fourth-century England, where Saxons continue to invade and kill.