An explosive powder called "atmos" leads to a frictional relationship between Conor, who believes it will be used to destroy them all, and Vorgeen, the leader of a neighbouring tribe who wants to create even more deadly weapons in order to protect his people.
The supposed cries of a wailing banshee turn out to be a beautiful girl troubled with a gift of foreseeing death. Conor must decide whether or not to protect the girl from the dangerous Kulan tribe after she tells him of his impending doom.
Conor and Fergus meet Doyle, a charismatic man leading a band of orphans and runaway children. Molly, the oldest girl in the group, reminds Fergus of the daughter he abandoned long ago. The attraction he feels for her, the attraction Molly feels and the jealousy that arise in Doyle as a result of these developing relationships have murderous consequences.
A long-held secret threatens to destroy them all when Conor discovers that Caitlin has been conversing with Roman soldiers and that a greedy Roman historian will go to any length to retrieve a precious scroll in her possession.
Conor discovers the spear that Longinus used to kill Christ on Golgatha and wields it to unite the Celtic tribes against the Romans. Concerned about the effect the spear is having on their friend, Caitlin and Fergus steal the relic and return it to its hiding place only to discover that Longinus is not far behind.
When the Druid "Father" declares that the head of each village must symbolically wed a Druid novice, Conor nervously prepares for his marriage. But a warning from a surprising source will lead him from wedded bliss to a face-to-face battle with his worst enemy
Conor desperately seeks a solution when an evil spirit possesses Catlin and threatens to destroy her. He discovers one of Galen's magic scrolls may hold the answer, however, unable to read it's symbols, he is forced to strike a dangerous bargain with Longinus in order to save her life.
Conor is invited to meet with the Maclir clan on a remote island to discuss unifying forces against the Romans. They've been lured into a trap as the Maclirs have already allied themselves with the Romans. Megan, their leader, has struck a bargain with Longinus and Diana to buy copies of the hundreds of booby traps spread around their island. But first, she must prove they work by killing Conor and his friends.
In the midst of fractious inter-tribal sparring at Queen Diana's castle, a rival warlord makes one demand before declaring war on everyone else: he wants Conor's latest rescue, a beautiful and mute maiden, to replace his murdered wife.