In July 1992, amidst the chaos of the Troubles in Northern Ireland, Detective Inspector Sean Duffy, now a part-timer in Scotland, is reluctantly pulled back to Belfast for a murder case. A carjacking gone wrong leads to the death of a solitary painter, who is revealed to be an IRA assassin. As Duffy investigates, he uncovers a web of conspiracy involving the CIA, MI5, and Special Branch, and he must navigate a perilous landscape to find the killer. This violent case could impact the fragile peace process, putting Duffy and his team in grave danger.