OUTSIDE EBBING, MISSOURI
*CUT TO THE CHASE*
NOTE: This spoiler was submitted by Jeremy
Mildred Hayes (Frances McDormand) drives down Drinkwater Road near her town as she passes by three vacant billboards. She goes to an advertising agency to speak to Red Welby (Caleb Landry Jones) about putting up three billboards for a year. Red determines Mildred is the mother of Angela Hayes (Kathryn Newton), who was raped and murdered seven months earlier.
Officer Jason Dixon (Sam Rockwell) is driving down Drinkwater Road when he sees two young men putting up the first billboard that reads "How come, Chief Willoughby?" He talks to a guy named Jerome (Darrell Britt-Gibson), who isn't fond of Dixon due to his reputation of harassing African-American citizens. Dixon passes the second billboard that says "And still no arrests?" He goes to read the last billboard (technically first to read), which says "Raped while dying". Dixon calls Chief Bill Willoughby (Woody Harrelson) as he's having dinner with his wife Anne (Abbie Cornish) and daughters Polly (Riyah May Atwood) and Jane (Selah Atwood) to inform him about the billboards.
The billboards receive widespread notoriety across town for the imagery people get from reading it, as well as what people believe to be a personal attack against Willoughby. Mildred's son Robbie (Lucas Hedges) is still traumatized by his sister's horrific death, and the billboards only make him more upset. Mildred even goes on live TV during a broadcast to explain her reasoning for putting up the billboards. She is essentially challenging the Ebbing Police Department, especially Willoughby, into doing their jobs instead of exercising force against minorities.
Mildred is at a pool hall where a drunk Dixon is trying to get in Red's face for allowing the billboards to go up. As Dixon tries to antagonize Mildred, she is defended by a local car dealer named James (Peter Dinklage), who tells her she looked good on TV.
Mildred goes home to find Robbie sitting at the table with Father Montgomery (Nick Searcy). He tells Mildred that Robbie told him how other kids at school are giving him problems for the billboards. As Montgomery tries to lecture Mildred, she brings up a point over some ads that ran a while back about people who were culpable by association with gangs if their friends did anything wrong, which she compares to people from church being culpable when one of them goes around sexually harassing young boys.
Mildred meets with Willoughby outside of town where they can overlook the billboards. He understands Mildred's grief and anger, but also mentions to her that he is dying of pancreatic cancer. Mildred already knows, as does most of the town.
After two people issue complaints over the billboards, Mildred visits one of them, a dentist named Geoffrey (Jerry Winsett). She grabs the drill from his hand and runs it through Geoffrey's thumb. Willoughby goes to the shop where Mildred works and brings her in for questioning after the incident. During her interrogation, Willoughby accidentally coughs blood in Mildred's face. She runs to get help and he is taken to the hospital.
While looking in Angela's old room, Mildred has a flashback to the last time she saw her. They were arguing over Angela going out, and Angela said she hoped she would get raped on the way, and Mildred agreed with her. The thought fills her with much regret.
Mildred's abusive ex-husband Charlie (John Hawkes) comes to Mildred's house with his airheaded younger girlfriend Penelope (Samara Weaving). Charlie gets into a confrontation with Mildred over the billboards for letting others know exactly what happened to Angela. He pushes Mildred against a wall while Robbie holds a knife to his throat. After Charlie lets Mildred go, he tells her that Angela had wanted to move in with him, and says she would still be alive if she did so. Charlie implies that Robbie knew. When Mildred asks, Robbie just says he doesn't know.
Mildred goes to the ad agency over the rent for the billboards, when Red's secretary Pam (Kerry Condon) brings in an envelope and note with the rent for keeping up the billboards a little longer. The donor of the money is kept anonymous.
Willoughby takes his family out to the lake so he can teach his daughters how to fish. Later that night, he makes love to Anne. As she falls asleep, Willoughby goes out by the stable and puts a bag over his head before he shoots himself in the head. Anne hears the gunshot and finds a note on the table written by Bill, and she breaks down crying when she realizes what has happened. His note to her explains that he couldn't bear to watch her and the girls suffer as his health continues to deteriorate, and he couldn't stand the physical pain he would endure from the cancer.
Everyone at the police department is devastated over what happened to Willoughby. Dixon in particular is so overcome with grief that he walks across the street to the ad agency to physically attack Red, even throwing him out the window (but not killing him). Dixon even punches Pam in the face on the way out, just as the new chief, Abercrombie (Clarke Peters) is walking by.
The news of Willoughby's suicide is featured on the news. When it is suggested that Mildred's billboards may have had something to do with it, she gets even more hatred from the residents in Ebbing. While dropping Robbie off at school, a student throws a can at her car. She gets out to confront the kid and kicks him in the nuts, along with a friend of his.
A man (Brendan Sexton III) enters Mildred's shop and throws a glass figurine at her. He suggests that he was a friend of Dixon's or possibly the man that killed Angela, but then he denies all of that and leaves, simply trying to scare Mildred. Anne enters moments later with a note that Willoughby left for Mildred. She reads it and learns that he was the one that paid the rent money for the billboards to keep drama going after his death.
At the station, Abercrombie enters and announces that he is Willoughby's replacement. Dixon insults Abercrombie and is promptly fired.
Mildred is driving home with Robbie at night when they see the billboards are all on fire. Mildred grabs an extinguisher while Robbie drives home for another. They put out the fires but the messages are destroyed.
Dixon is called by the desk sergeant at the station to go pick up a note left for him. He goes at night when Abercrombie isn't there, while Mildred sneaks into the ad agency after believing that Dixon set fire to her billboards. Dixon finds the note, another written by Willoughby. It says that Willoughby knew Dixon wanted to become a detective and he believed that Dixon has what it takes to do so, but he needs to be more loving and compassionate to do so. Mildred then starts hurling Molotov cocktails at the station. Dixon gets out of the burning building while saving Angela's case file, but he gets badly burnt. Mildred runs out as James shows up to put out the fire on Dixon's body. After the authorities show up, James provides Mildred with an alibi saying she was with him. Grateful, she agrees to go to dinner with him.
Mildred is visited by Jerome, who has received duplicates of the billboards after the fire. He, James, and Mildred's coworker Denise (Amanda Warren) help Mildred put them back up.
Dixon mostly recovers from his wounds and is at the bar. The man that threatened Mildred at her store enters with a buddy. He starts bragging about raping a girl seven months earlier, which Dixon overhears and believes he is talking about Angela, especially since the guy mentions dousing her with gas, and Angela's body was burnt. Dixon approaches the guy and pretends to do a magic trick, but he just scratches the guy's cheek, leading him to start beating the crap out of Dixon until his buddy talks him down. Dixon goes home and takes a piece of skin from under his fingernail to send in as a DNA sample.
Mildred is at dinner with James when Charlie and Penelope walk in. Charlie approaches Mildred and admits he set the billboards on fire while drunk and angry, but he was convinced by Penelope that "anger only begets more anger". After a while, James figures Mildred is uncomfortable with their date because James is a small person, and he leaves after paying. Mildred walks over to Charlie and Penelope's table with a wine bottle as if to use it on them, but she instead sets it down and tells Charlie to be good to Penelope.
Dixon contacts Mildred with the news that he may have found Angela's killer. However, after the results come back, Dixon meets with Abercrombie to find out that the man was not Angela's killer, as he was stationed in the Middle East around the time of her murder, and the DNA samples don't match. Dixon calls Mildred again to tell her the news, both of them extremely disappointed with the results. He does note that the man is still a rapist, and Dixon got his license plate number.
Mildred and Dixon head off to Idaho where the man lives to take matters into their own hands. On the drive there, Mildred admits she set fire to the police station. Dixon already knew since, "Who else could it be?" The two of them then contemplate the decision of killing the man when they see him, but they figure they'll decide once they get there.