Ex-boxer Douglas ‘Arm’ Armstrong (Cosmo Jarvis LADY MACBETH, PEAKY BLINDERS) is the faithful and violent right-hand-man to the drug-dealing Devers clan, ready to dole out beatings at the whim of his best friend, and the family’s unpredictable protégé, Dympna (Barry Keoghan DUNKIRK, AMERICAN ANIMALS). Arm’s struggle to find his place in the world has consequences on his relationship with his ex-girlfriend Ursula (Niamh Algar THE VIRTUES, THE LAST RIGHT) as she strives to find a better life for herself and their young son Jack.