This fictional novel about Catholicism in Wales and Ireland focuses on the clash between paganism and Christianity through interesting tales of intriguing characters, specifically Saint Brendan.

One of the key characters, Bishop Erc, was once a druid who converted to Christianity after meeting Saint Patrick. He was

weaned from druidry by the sainted Patrick, at the sound of whose name the angels wet their holy breeches

Erc states,

God is the wind that blows over the sea . . . the wave of the deep . . . the bull of the seven battles . . . the tear in the eye of the sun.

When Brendan is born, Erc proclaims that Brendan has a special calling on his life and will be devoted to Christian works:

The boy was to be raised to the glory of the new and grand God that Patrick had brought them from over the water.

Bishop Erc becomes an influential mentor to Brendan from an early age, as Erc takes Brendan away from his parents at the age of one to raise him up as a saint. Brendan has many journeys and voyages in which he seeks to spread Christianity. When he joins the "blue martyrs, he does so to

scour the blue storms of the sea for the peace of God.

Brendan becomes a devoted to bring peace throughout lands and doing good works. He proclaims that

there's only one true port; that's Heaven.

At the end of Brendan's life, Brendan bemoans his shortcomings.

I fear the sentence of the judge.

Yet, Brendan's close friend, Finn, states (about Brendan):

I’d sentence him to have mercy on himself. I’d sentence him less to strive for the glory of God than just to let it swell his sails if it can.