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 a windswept fishing village, a mother is torn between protecting her beloved son and her own sense of right and wrong. A lie she tells for him rips apart their family and close-knit community.