The Celtic army receive a thousand pounds in weight of gold in payment for abandoning their capture of Rome. They accept the huge payment and head home. The Chieftain, Brennus, traverses back through the Alps whilst our Silurian warriors head west to the port of Civita Vecchia in search of a sea passage to return to their homeland. During this voyage, they meet a salt trader from Hallstatt who owns several salt mines. However, the bronze tools his men are using are failing and he needs to find stronger and more robust tools to access the untapped mountains of salt that lie deeper underground.Their vessel is attacked whilst crossing the sea by a Carthaginian warship. During this skirmish, the salt trader witnesses the shattering of the Carthaginian leader's bronze sword by the Celt's weapon - a sword that he later discovers was made from iron. This new metal could be the answer he has been looking for in his quest to fabricate stronger tools.

The battle sees our Celtic hero Arenwen making a new enemy, one who will follow him through the Pillars of Hercules, desperate for revenge. The adventure sees them putting to many ports to re-stock their supplies where they discover new and ancient lands where they enlist the tribes to help them along their journey.Our heroes return to their home town of Pont-y-ty-pridd where they manufacture iron tools and weapons for the salt trader - the man who trades in white gold.