Jimmy is killed by the police after killing a cop without provocation. Marcus gets a stable job outside the city, and asks Patricia and Iris to move away with him, but Patricia refuses to leave, so Marcus leaves alone.
Marcus Washington (Anthony Mackie), a former leader of the Black Panthers, returns to his hometown of Philadelphia after having disappeared a number of years ago. The reception he gets from his old friends is generally frosty. He has spent some time in jail, and the rest living out of his car and journeying cross-country. Marcus had left town after his good friend Neil, another leader of the Black Panthers movement, was shot by the police. Many, including former Panther and now gang leader DoRight, believe Marcus snitched on his friend.
Neil's widow Patricia (Kerry Washington) still lives in the house where Neil was shot with their daughter Iris. Patricia was also a Panther, and still works to protect the downtrodden and disenfranchised within the community. One such person is her cousin Jimmy (Amari Cheatom), who is angry at the world and constantly gets in trouble for harassing police officers (who may or may not be racist). Patricia is also dating a wealthy man who begrudgingly finances much of her endeavors. Patricia has refused to tell Iris about her dad's death. She is also excited to find Marcus back in town. When she finds Marcus has nowhere to stay, she invites him to move in with her and Iris.
Marcus and Iris grow closer, as do he and Patricia. Marcus constantly warns Jimmy to abandon his anger and tells him that the Panthers were largely wrong in their struggle. Jimmy doesn't listen and grows more violent. Patricia's boyfriend is unhappy that she won't leave her house (and her community) to move in with him and eventually breaks up with her. She and Marcus soon have sex and he becomes more protective of Iris. Eventually, he tells Iris the story of her dad's death, stating that Neil had been planning an assault against the police in retribution for them attacking a community member and, realizing that such action would endanger everyone, Marcus turned him in. Later, Iris finds the part of the wall with Neil's bloodstains from where he was shot by the police (the wall having since been wallpapered).
Ultimately, Marcus is contacted by the police who want to take down DoRight and his gang. They want Marcus to plant a gun in DoRight's bar that will implicate him in a crime, and to also get statements from him while wearing a wire. The police tell Marcus that if he doesn't work with them, they will reveal that it was actually Patricia, and not Marcus, who snitched on Neil (Marcus was just covering for Patricia). Marcus goes to the bar, but instead, decides not to plant the evidence and warns DoRight that the police are after him
Later that night, Jimmy, dressed in Panther regalia, shoots one of the cops who had harassed him earlier. Jimmy flees to Patricia's house, putting Iris and Patricia in danger. Eventually, the police get a warrant to enter the house, though Jimmy has already fled. The police eventually find him in the woods and kill him. Marcus gets a job offer out of town, and asks Patricia and Iris to come with him, noting that with Neil and Jimmy gone, she has nothing left for her in Philadelphia. Patricia refuses to leave her home and her community (just as she refused to leave with her ex-boyfriend), so Marcus is forced to leave without them, likely never to return.