Emerald Earth, Emerald Ice: Book Three, Emerald Series

This is the third in the Emerald Series, a family saga that began with a love triangle between the half-Cherokee Karensa and two men, John Jean, a missionary in Venezuela, and Bart, a sheriff in Arizona. The third book finds Bart and Matt in Nova Scotia starting over. As the children mature to adulthood, they make serious choices about their lives and discover a secret that almost shatters the family.