During the American Revolution in 1776, Benjamin Martin, a veteran of the French and Indian War and widower with seven children, is called to Charleston to vote in the South Carolina General Assembly on a levy supporting the Continental Army. Fearing war against Great Britain, Benjamin abstains. Captain James Wilkins votes against and joins the Loyalists. A supporting vote is nonetheless passed and against his father's wishes, Benjamin's eldest son Gabriel joins the Continental Army.
Four years later in 1780, Charleston falls to the British and a wounded Gabriel returns home carrying dispatches. The Martins care for both British and American wounded from the nearby battle, before British Dragoons, led by the ruthless Colonel William Tavington, arrive, arrest Gabriel, and take the Martin family slaves. When Benjamin's young son Thomas tries to free Gabriel, he is shot and killed by Tavington, who orders the Martins' house burned and wounded Americans executed. After the British leave, Benjamin gives his next two eldest sons muskets and they ambush the British unit escorting a tied Gabriel. Benjamin skillfully, yet brutally, kills many soldiers with his tomahawk. A British survivor tells Tavington of the attack, earning Benjamin the moniker of the "Ghost". Benjamin and Gabriel resolve to fight the British, leaving the younger children in the care of Benjamin's sister-in-law, Charlotte. On their way to the Continental Army's camp, they witness the southern Continental Army under General Horatio Gates engaging the British Army. Benjamin recognizes the foolishness of the action and sure enough, the Continentals are decisively routed.