Jacob is a steadfast Loyalist. Eli is a newcomer to Upper Canada, whose family has just moved from the American South. The two boys become fast friends, but their friendship is tested when Eli's father refuses to pledge allegiance to the Crown. As Loyalists in Upper Canada become more and more suspicious of those with American leanings, the looming war threatens to pull the boys and their town apart. Peopled with key figures from the War of 1812, such as General Isaac Brock and newspaperman-turned-traitor Joseph Willcocks, Brothers at War portrays the tense era just before the War of 1812, which pitted neighbour against neighbour as Upper Canada prepared to fend off invading American forces.