Scotsman Ewan MacBride and German Peter Baum, both have 'histories' from their homelands that force them to stow away aboard a ship bound for Canada. With skills in blacksmithing and cooperage, the two men soon forge a brotherly friendship and together build a successful business in the thriving harbour city of Halifax, Nova Scotia. However, with the outbreak of World War I, the two friends find themselves on opposite sides, wearing the uniforms of the Canadian Expeditionary Force and the German Imperial army. The Heathery Isle brings to vivid life many historic battles including Ypres, Vimy Ridge, Verdun, Passchendaele, and the Last 100 Days, plus the sinking of the Titanic and the Halifax Explosion. As these two young men come of age in the battlefield trenches, they develop a mutual loathing for war and a deep longing to be reunited with their wives and the young children they barely know.