Patrick's ten-man mission arrives by boat in the Irish kingdom of Brega, and they are immediately expelled by the king's warriors. Rowing north, they find refuge with a group of outlaws, and from these humble beginnings create their first church.

When Patrick lights an Easter fire and falls foul of druid custom, at the time of a national gathering of kings, near to Tara, Matho, the Arch-druid of Ireland arranges that Patrick should answer to the High King. But Matho is trapped by his own lies, enabling Patrick to turn the hearing to his advantage, winning the High King's acceptance of his mission whilst the arch-druid is stripped of his seniority - ensuring Matho's lifelong antagonism towards Patrick.

Patrick loses a champion on the death of High King Niall, suffering further when the succeeding king restores Matho to power. The Arch-druid cunningly plots a spectacular atrocity, to ruin Patrick's thriving church, culminating in the burning of Patrick at the stake. As flames lick at the hem of Patrick's robes, 'Where is your god now?' Matho taunts.