In 1807 Napoleon Bonaparte controls most of continental Europe and expects the invasion of Portugal to be a quick side campaign. This film tracks how it instead became the Spanish Ulcer, the drawn-out conflict that started bleeding his empire dry. It covers the Madrid uprising against French occupation, the improvised and often disorganized Spanish resistance that formed in its wake, and the arrival of a small British expeditionary force under Sir John Moore. Moore's brutal winter retreat to Corunna, fought through mountains and freezing weather with Napoleon's army in pursuit, gets extended attention as the campaign's defining ordeal. Historians work through maps, battlefield locations, and contemporary accounts to explain how a war Napoleon expected to win in a single summer turned into a running sore that drained French manpower and morale for years. The film also connects the events to their fictional afterlife, noting how Bernard Cornwell's Richard Sharpe novels drew directly on this same campaign. It is a straightforward, well-sourced account of the opening two years of a war that helped unravel the Napoleonic empire.