Knuckle navigates the grimy world of Irish Traveller bare-knuckle boxing, depicting it as a sport existing somewhere between mindless violence and communal catharsis. Following a series of feuding families over the course of twelve years, filmmaker Ian Palmer uncovers a story with roots in a manslaughter but which has taken on a life of its own, with each fight creating grievances which demand another. Principally accompanying the Quinn McDonagh family as they pursue their various feuds, Palmer finds the mixture of honour, sweat, and money drives the fighters from one bloody bout to the next. Unearthing a bizarre, contradictory world Knuckle is a compelling depiction of how familial pride embroils the fighters in a wide underground network of bloodshed and recrimination.