The Chronicles of Iona

It is 574 A.D. Columba and Aedan mac Gabran hunt down their enemies through the wilds of Ireland's ancient north and west. Their quest? To find Aedan's lost brother, to unite the warring peoples of Dal Riata, and to defeat once and for all the tyrannical overlord who holds them all hostage.
But an even greater enemy threatens: bubonic plague ravages Europe yet again, bringing the West to its knees-a mortal peril from which none of them may escape.
Ranging across the storied landscapes of early-mediaeval Donegal, Northern Ireland, and the Isle of Man, 'Cradle of Saints', the timely fourth instalment of this epic series, continues the stirring tale of the two men who helped to found the monastery of Iona and the nascent kingdom of Scotland.