Cosmo Jarvis and Barry Keoghan star in Nick Rowland’s adaptation of Colin Barrett's acclaimed collection of short stories. In darkest rural Ireland, ex-boxer Douglas 'Arm' Armstrong has become the feared enforcer for the drug-dealing Devers family. He's 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's asked to kill for the first time, and his attempt to do the right thing endangers everyone he holds dear.