Plot

Offered a plea deal by the FBI, William O'Neal infiltrates the Illinois chapter of the Black Panther Party to gather intelligence on Chairman Fred Hampton.

Fred Hampton, a young, charismatic activist, becomes Chairman of the Illinois chapter of the Black Panther Party - putting him directly in the crosshairs of the government, the FBI, and the Chicago Police. But to destroy the revolution, the authorities are going to need a man on the inside.

FBI informant William O'Neal (LaKeith Stanfield) infiltrates the Illinois Black Panther Party and is tasked with keeping tabs on their charismatic leader, Chairman Fred Hampton (Daniel Kaluuya). A career thief, O'Neal revels in the danger of manipulating both his comrades and his handler, Special Agent Roy Mitchell (Jesse Plemons). Hampton's political prowess grows just as he's falling in love with fellow revolutionary Deborah Johnson (Dominique Fishback). Meanwhile, a battle wages for O'Neal's soul. Will he align with the forces of good? Or subdue Hampton and The Panthers by any means, as FBI Director J. Edgar Hoover (Martin Sheen) commands?

In 1966, after getting in trouble with the law,William O'Neal,a bold 17-year-old car thief, cuts a deal with FBI agent Roy Martin Mitchell. As a result, Bill must infiltrate the Illinois chapter of the Black Panther Party, a black power political group led by charismaticFred Hampton,in exchange for having his charges dropped. But FBI DirectorJ. Edgar Hooveraims to dismantle the Black Panthers, whom he has already classified as a threat. Meanwhile, the unapologetic young revolutionary rises within the organisation, forming unexpected but powerful alliances, including the Rainbow Coalition, a multicultural movement. However, with an informant planted in the heart of the political organisation to work as the FBI's eyes and ears, the impostor finds himself increasingly trapped by his web of lies. What will it take for the government to stop the influential black Messiah's radical activism?—Nick Riganas

In the late 1960s, 17-year-old petty criminal William "Bill" O'Neal is arrested in Chicago after attempting to hijack a car while posing as a federal officer. He is approached by FBI Special Agent Roy Mitchell, who offers to have O'Neal's charges dropped if he works undercover for the bureau. O'Neal is assigned to infiltrate the Illinois chapter of the Black Panther Party (BPP) and its leader, Fred Hampton.

O'Neal begins to grow close to Hampton, who works to form alliances with rival gangs and militia groups while extending community outreach through the BPP's Free Breakfast for Children Program. Hampton's persuasive oratory skills eventually help to form the multiracial Rainbow Coalition. Hampton also falls in love with Deborah Johnson, a fellow BPP member. O'Neal begins to relay intel to Mitchell, who in return compensates him with money. When a fugitive Party member, George Sams, hides out at the local BPP office, O'Neal learns from Mitchell that Sams is an informant whose presence in BPP offices allows the bureau to obtain search warrants.

After Hampton is arrested and imprisoned, O'Neal begins to rise through the ranks and is promoted to security captain. When a shootout between the Chicago Police and the BPP occurs at the chapter office, O'Neal sneaks out as the office is bombed by the police. Afterward, O'Neal attempts to quit being an informant but is rejected by Mitchell.

After Hampton is released from prison while appealing his charges, he reunites with Deborah, now pregnant with his child. A BPP member, Jimmy Palmer, who was hospitalized after being shot by a police officer, is killed while being transferred to another hospital. Enraged upon learning of Jimmy's death, fellow member Jake Winters engages in a shootout with police, killing several officers before being gunned down himself.

After Hampton's appeal was rejected, FBI Director J. Edgar Hoover orders Hampton be "neutralized" before he returns to prison. Mitchell corners O'Neal into helping with the plan by warning him that the BPP will retaliate against him if they find out he's an informant, and O'Neal reluctantly agrees to help. O'Neal is later handed a vial of sedatives and ordered to drug Hampton's drink with it. The next evening, BPP members gather at Hampton's apartment before he departs for prison. An allied gang leader offers Hampton money for him to flee the country with, but he turns it down and instead orders a trust to be established with the money under Jake's name. As the evening progresses, O'Neal reluctantly drugs Hampton's drink and departs soon after. Hours later, officers and agents raid the apartment and shoot Hampton dead. Later, O'Neal meets with Mitchell, who gives him money and a pair of keys to a gas station he now owns. O'Neal attempts to quit again, but reluctantly accepts the money and keys and places them into his pocket.

The film ends with archive footage of Hampton's speeches, his funeral procession, and an interview O'Neal gave in 1989. The title cards state that O'Neal continued to work as an informant within the BPP before committing suicide. A lawsuit was filed against the FBI in 1970 and 12 years later was settled for $1.85 million. Today, Fred Hampton Jr. and his mother serve as chairman and board member of the Black Panther Party Cubs.