Mildred (Frances McDormand)'s daughter was raped and killed while out. 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 dependence. In a blink of an eye, a few months have passed, and the case is still unsolved, and the police seem to have already shifted their attention from the case. Mildred, who was entangled in despair and pain, rented three giant billboards on the side of the highway, accusing the police of incompetence in handling the case, and pointed the spearhead directly at the Chief of Police Willoughby (Woody Harrelson). In fact, Willoughby has been hiding the fact that he is terminally ill and will not live long. Because of these three billboards, Mildred and Willoughby's lives have changed dramatically.