Three

Mildred Hayes's life is profoundly affected by the tragic loss of her teenage daughter, Angela, who was brutally assaulted and murdered seven months ago. This event serves as the catalyst for her subsequent actions and desperate search for justice.

In a bold move to draw attention to her daughter's unsolved case, Mildred rents three abandoned billboards near her home. The messages on the billboards challenge the local authorities, specifically questioning Sheriff Willoughby about the lack of progress in the investigation.

The billboards trigger outrage among the townspeople, including Sheriff Willoughby and Officer Dixon. While Willoughby understands Mildred's frustration, he feels the billboards reflect poorly on his character, further complicating the situation.

Despite facing harassment and threats from the community and her abusive ex-husband Charlie, Mildred remains resolute in her pursuit of justice for Angela. Her son Robbie, struggling with the aftermath of their loss, is distressed by her determination.

Sheriff Willoughby, who is suffering from terminal pancreatic cancer, exhibits sympathy towards Mildred's plight but is conflicted about her public protest. His terminal illness adds a layer of complexity to his role in the investigation.

After an altercation at a dentist's office, where Mildred injures her dentist, she is brought in for questioning by Willoughby. During the interview, he unexpectedly coughs up blood, revealing the severity of his health crisis.

After leaving the hospital against medical advice, Willoughby spends a final cherished day with his family. Later, he commits suicide, leaving notes explaining his decision and expressing that Mildred's actions were not to blame for his death.

In the wake of Willoughby’s death, Officer Dixon's anger leads him to assault Red, the billboard rental agent. This violent act is witnessed by Abercrombie, who subsequently terminates Dixon's employment.

In a shocking act of aggression, the billboards erected by Mildred are destroyed by arson. This becomes a pivotal moment in the story, illustrating the lengths to which people will go to silence her efforts for justice.

In response to the destruction of the billboards, Mildred retaliates by throwing Molotov cocktails at the police station, believing it to be unoccupied. However, Dixon is present, leading to an explosive encounter.

After recovering from his injuries, Dixon learns about a man in a bar who boasts about an incident similar to Angela's murder. He collects the man's DNA as new evidence, hoping to find a lead in the case.

Mildred goes on a date with James to thank him for providing her with an alibi after the police station incident. During the date, her ex-husband Charlie arrives and reveals his involvement in burning the billboards, deepening her distress.

Dixon learns that the DNA he collected does not match any evidence found at the crime scene and that the suspect was overseas when Angela was murdered. He realizes that the truth may lie elsewhere, prompting him to continue his investigation.

Determined to seek justice, Mildred and Dixon embark on a journey to Idaho after concluding that the man may be guilty of another sexual offense. They face their doubts about the morality of their mission, yet they agree to proceed.