Eight Dublin schoolboys and their teacher travel to a remote fishing village on the west coast of Ireland to celebrate the Celtic feast of Mid-Summer Night. It is there, back in the year 1631, that the notorious Barbary pirate, Morat Rais, captured one hundred and thirty men, women, and children, and carried them away to the North African coast of Algiers. The villagers were never heard from again.

What happens when the boys' trusted teacher, Mr McDonagh, takes on a new skin? What happens when ancient Celtic spirits rise up and catapult the young travellers and their teacher back in...