In 1846, on the eve of the Mexican American War, hundreds of Irish-Catholic immigrants under the command of abusive, Protestant officers fled the American Army and joined the other side. They were formed into a special unit under their inspirational leader, John Riley. Known as the St. Patrick's Battalion, they became the fiercest and most feared artillery unit in the Mexican Army.Loyal Son is the fictional story of one of those San Patricios, eighteen year old Patrick Ryan from County Cork, Ireland. On the brink of losing their farm, his father entrusts him with their life savings and sends him to America to purchase land and establish roots. He and his sister arrive at their uncle's house in Philadelphia a week before anti-Catholic Bible Riots erupt. When rabid Nativists invade their neighborhood, Patrick joins his cousins to resist them. During the three days of violence, the family's house is burnt to the ground and with it all of Patrick's money.Desperate to make it right and fulfill his duty, Patrick joins the army for the enlistment bonus of one hundred and sixty acres of land. His only goal is to get a farm and see his father, mother and brothers join him and his sister in the Promised Land of America. Nothing worked out the way any of them hoped.