The English Civil War split the country not just by class or creed but by geography, and this episode maps which counties backed Charles I and which sided with Parliament. Historians walk through the regional loyalties that hardened as relations between king and Parliament broke down, from royalist strongholds in the north and west to parliamentary power bases in London and the southeast. The film uses maps, reenactment footage, and expert interviews to explain why a market town might arm itself against its own neighboring county, and how those local rivalries fed into the wider war that pitted father against son. Portraits of the key figures on both sides, including the king himself, anchor the broader account of how Britain's political map got redrawn county by county. The episode treats the war as a nationwide argument fought street by street rather than a single clean battle line, and it stays grounded in specific places and the men who held them.