The Riddle Walker

Because of a small, careless action in the medieval past, the Allied Forces may not win World War 2 after all.

Bhaird, second son of a Scottish lord, is heartbroken when his father is killed in a hunting accident, and the three MacDonald brothers are divided to rule their inheritances. While his brothers are given pieces of Scotland, Bhaird, bitter and angry, must cross the sea to Ireland. Oleron decides to come along on the journey. But as the brothers set sail, the sea churns and takes their ships under...
And when they surface, the brothers find themselves in the far future. In the midst of the second World War.