the-guard-locandinaSergeant Gerry Boyle (Gleeson) is an officer of the Garda Síochána in Connemara in the west of Ireland. He is crass and confrontational, regularly partaking in drugs and alcohol even while on duty. He is also shown to have a softer side, showing concern for his ailing mother, Eileen (Flanagan).

Boyle and his partner, Aidan McBride (Keenan), investigate a murder in their jurisdiction, with evidence pointing to an occult serial killer. Shortly after, Boyle attends a briefing by Wendell Everett (Cheadle), a special agent of the FBI, sent to liaise with the Garda in hunting down four Irish drug traffickers, led by Francis Sheehy-Skeffington (Cunningham), who is believed to be awaiting a delivery of cocaine coming into Connemara by boat…