Ireland, 1970s. Eager to leave his dark past behind, Finbar Murphy (Liam Neeson) leads a quiet life in the remote coastal town of Glen Colm Cille, far from the political violence that grips the rest of the country. When a menacing crew of terrorists arrive, led by a ruthless woman named Doireann (Kerry Condon), Finbar soon discovers that one of them has been abusing a local young girl. Drawn into an increasingly vicious game of cat and mouse, Finbar must choose between exposing his secret identity or defending his friends and neighbors.