December, 1920: Mary Margaret Kincade, known as Peg, a devout Catholic, is the only child of an Irish adventurer presumed dead in an Arctic expedition gone awry. When her odious cousin comes to take over the family business and presumes to force Peg into marriage, she decides to make a new life in America by working her way across the ocean on a cruise liner.Liam Cormac, a Protestant member of the Irish Republican Army, fighting for freedom from English rule, signs on to the same ship with the intention of blowing it up in the middle of the ocean. Liam and Peg encounter each other in the first class passenger lounge and the attraction is mutual. When Peg is taken hostage by Liam's partner, Liam has to make a decision about where his loyalties lie- with his country and his mission or with an Irish Catholic lass.