Oliver Cromwell's 1649 campaign in Ireland sits at the center of this film, tracing how a war that began in England over the power of Parliament and the crown spread into an Irish conflict of even greater brutality. The documentary follows Cromwell's New Model Army through the sieges of Drogheda and Wexford, where garrisons and civilians were killed in numbers that still shape Irish memory of his name centuries later. Historians walk the ground where these sieges happened and read from contemporary accounts and letters to weigh what Cromwell himself claimed about the killings against what the record shows. The film sets his Irish campaign against the wider English Civil Wars, showing how a domestic quarrel between king and Parliament hardened into a religious and colonial war once it crossed the Irish Sea. Portraits of the commanders on both sides, Catholic Confederate and Cromwellian, give the violence specific faces rather than treating it as an abstract atrocity, and the film ends with Cromwell's legacy still contested rather than settled.