Southern California, 1962. Two Irishmen, claiming to be cousins, inform Patrick Lyons that he is the heir to the Lyonsmaine estate in Ireland. He seeks the help of genealogist Tracy Mayfield to find out whether it's a scam or not.
Tracy takes Patrick to Ireland during a ceasefire in the Irish unrest to learn about Patrick's inheritance.
They join her uncle, Tex Mayfield, and Chad Haines, both former intelligence operatives.
Patrick's life spirals down as the four are thrown into a boiling cauldron of secret preparations for war by the Irish Republican Army. This magical emerald isle seems cursed.