Mildred (Frances McDormand)'s daughter was brutally raped and murdered while away. The marriage between Mildred and her husband Charlie (John Hawkes) came to an end. Now, she and her son Robbie (Lucas Hedges) live a life of each other. Months passed in the blink of an eye, but the case still had no sign of being solved, and the police seemed to have shifted their attention away from the case. Enraged by despair and pain, Middred rented three giant billboards on the highway, accusing the police of incompetence in handling cases, and directed the blame at Police Commissioner Willoughby (Woody Harrelson). In fact, Willoughby has always concealed the fact that he is terminally ill and will soon die. Because of these three billboards, the lives of Middred and Willoughby have undergone earth-shaking changes.