In a small Missouri town, a grieving mother confronts the local authorities' failure to catch her daughter’s murderer by taking a bold step. She rents three decaying billboards on a rarely traveled road to call out the town's revered chief of police for not making any arrests. The provocative message on the billboards ignites a controversial reaction from the community, drawing media attention and creating a ripple effect that impacts several townspeople’s lives.

The woman's direct challenge to law enforcement incites a variety of responses from the town's citizens, further deepening the divide between them. While some support her quest for justice, others view her actions as detrimental to the town's image and harmony. The abrasive police officer with a troubled past becomes particularly entangled in the conflict, leading to a sequence of events that begins to unravel the deeply rooted issues within the town. As the story unfolds, the characters are forced to confront their own prejudices and the consequences of their actions.