Gone for a decade, Terry Noonan (Sean Penn) is welcomed back into the fold in his Irish-American neighborhood in New York City. A one-time street tough, Terry is now an undercover officer targeting crime boss Frankie Flannery (Ed Harris). In the name of duty, Terry rekindles his dormant friendship with Frankie's younger brother, Jackie (Gary Oldman). But as Terry gets closer to his goal, his feelings for the youngest Flannery, his old flame Kathleen (Robin Wright), complicate his mission.