Jamie, trying to process the death of her mum and fighting with her protective sister, steals a car and drives north to buy fireworks.
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.