In darkest rural Ireland, ex-boxer Douglas 'Arm' Armstrong has become the feared enforcer for the drug-dealing Devers family, whilst also trying to be a good father to his autistic five-year-old son, Jack. Torn between these two families, Arm's loyalties are truly tested when he is asked to kill for the first time.

In this radically reimagined American Western set towards the end of the Civil War, Southerner Augusta encounters two renegade, drunken soldiers who are on a mission of pillage and violence. After escaping an attempted assault, Augusta races back to the isolated farmhouse that she shares with her sister Louise and their female slave Mad. When the pair of soldiers track Augusta down intent on exacting revenge, the trio of women are forced to take up arms to fend off their assailants, finding ways to resourcefully defend their home––and themselves––as the escalating attacks become more unpredictable and relentless.