Why the Ambiguous Ending of "Three Billboards" Works

Originally published on TheScriptLab.com

Scores of films have ambiguous endings. American Psycho, Shutter Island, The Graduate, Inception, Birdman, Black Swan, Donnie Darko, even this year’s The Shape of Water — the list goes on.

There is a reason that these films, despite leaving a huge question in the minds of the audience members, feel complete.

Take Martin McDonagh’s Three Billboards Outside Ebbing, Missouri, which recently won four Golden Globe Awards and three Critic’s Choice Awards. The story follows Mildred Hayes, a tough single mother, as she goes up against the local police force that has seemingly ignored the case of her daughter’s rape and murder. Mildred’s actions reverberate around the town, through her personal life, and into that of the people around her. She comes head-to-head with Chief Willoughby and Officer Dixon, wracked with guilt and anger over what happened to her daughter.

But, in the end, spoiler alert, after Mildred and Dixon team up to find and kill a man they suspect has done equally heinous crimes as the one committed by the man who ended her daughter’s life, both admit they don’t know if they’ll go through with it. Then we cut to black and the credits roll.

McDonagh doesn’t share if Mildred and Dixon continue on and kill the man. He doesn’t share the aftermath of their decision, or if they find the man at all. He doesn’t even share if Mildred ever finds who murdered her daughter.

He doesn’t have to.

The ambiguous ending of Three Billboards — and, I’d argue, of all the films I mentioned above and most of all films that feature ambiguous endings — works because of one simple reason.

The key to creating a narrative that simultaneously remains open-ended but feels closed lies in completing the character arcs. If the character’s story, their physical and/or emotion journey, resolves itself in some way, it’s okay that the screenplay not answer every single lingering question.

These endings cannot be willy-nilly applied to every screenplay though, and screenwriters should take care when employing this way of ending things in their scripts. Only certain types of stories can support the open-ended-ness of an ambiguous, unfinished ending.

Three Billboards can feature an ending that never solves Abigail Hayes’ murder because the story was never really about the crime to begin with — it was about forgiveness, justice, and guilt.

By the end of the film, Mildred hasn’t changed from the hardened, spitfire of a woman she was at the beginning. But she has come to forgive herself, if only a little, for her part in what happened to her daughter, and she has realized that the police, like she herself, can only do so much.

Mildred’s complete character arc — the drastic, yet subtle change that she undergoes throughout the course of the film — is the reason McDonagh was able to finish on an ambiguous ending.

In order for an ambiguous ending to be truly effective, the screenwriter must create a situation in which the main character’s journey is complete, even if the “story” (in the traditional sense of the word) isn’t. If the main character’s journey, whatever that may be, is complete, the narrative is as well.

So even though, like Mildred, the audience doesn’t have all the answers as they walk out of the theater, the ending feels justified.