Mildred Hayes, played by Frances McDormand, is in a state of deep sorrow as she grapples with the traumatic loss of her teenage daughter, Angela, portrayed by Kathryn Newton, who was tragically assaulted and murdered seven months earlier. Frustrated by the lack of significant progress in the investigation into Angela's death, Mildred takes a bold step to draw attention to her plight. She rents three dilapidated billboards situated near her home, emblazoned with the provocative phrases: "RD WHILE DYING", "AND STILL NO ARRESTS?", and "HOW COME, CHIEF WILLOUGHBY?"* This audacious act provokes a strong backlash from the local community, including Sheriff Bill Willoughby, played by Woody Harrelson, and the overtly racist officer Jason Dixon, portrayed by Sam Rockwell. Adding to the tension is the community's awareness of Willoughby's terminal pancreatic cancer, making Mildred's actions even more controversial, especially because Willoughby is generally respected as a good man.
Despite her son Robbie, played by Lucas Hedges, being distressed by the situation, Mildred remains steadfast in her conviction. The scrutiny and intimidation escalate as Sheriff Willoughby sympathizes with her frustrations but feels personally attacked by the billboards. In his attempt to restore order, Dixon resorts to harassment, threatening the billboard renter Red, played by Caleb Landry Jones, and falsely arresting Mildred's coworker Denise, portrayed by Amanda Warren, on minor drug charges. Compounding her trauma, Mildred also faces confrontations from her abusive ex-husband Charlie, played by John Hawkes, who irresponsibly blames her for their daughter's tragic fate.
However, the situation takes a dramatic turn when Willoughby, who appears to be understanding of Mildred’s anger, suffers a bloody coughing episode during an interview with her. Choosing to leave the hospital against medical advice, he spends one last beautiful day with his wife Anne, portrayed by Abbie Cornish, and their daughters before ultimately deciding to take his own life. In a poignant farewell, he leaves notes for multiple people, one of which reassures Mildred that she was not a reason for his demise, and he even financially supports the continued display of her billboards out of a shared sense of humor about the chaos that would ensue.
The death of Willoughby sends shockwaves through the community, and Dixon’s violent reaction towards Red and his assistant becomes a point of concern, especially as it is witnessed by Willoughby’s replacement, Abercrombie, played by Clarke Peters, who promptly dismisses Dixon. The billboards themselves face destruction via arson, compelling Mildred to retaliate by launching Molotov cocktails at the police station, under the belief that no one is inside. However, Dixon is there and uses this opportunity to reflect on a letter Willoughby left him, one that encourages a shift away from hate towards a path of love—an ironic twist given his previous actions.
After exiting the hospital, Dixon gains crucial information while eavesdropping on a bar patron boasting about a crime similar to Angela's murder. Seizing the moment, he gathers DNA from this suspect, further intertwining their fates. Meanwhile, Mildred's situation becomes increasingly complex as she finds herself on a date with James, played by Peter Dinklage, who provides her with an alibi. Unfortunately, the evening takes a painful turn when Charlie arrives with his young girlfriend Penelope, portrayed by Samara Weaving, revealing his involvement in the destruction of the billboards.
As the plot thickens, Abercrombie informs Dixon that the DNA doesn’t match any evidence from Angela's case, leading them both to suspect the man is involved in other sexual assaults. United in their quest for justice, Mildred and Dixon embark on a journey to Idaho armed with a weapon, grappling with their ethical dilemmas as they progress. The tension mounts as they navigate their conflicting emotions and contemplate their next steps on their daunting mission for truth and retribution.
