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.