It takes an especially capable director to incorporate levity into a film about a mother pushing for further investigation into the rape and murder of her daughter, but in Three Billboards Outside Ebbing, Missouri, Martin McDonagh (Seven Psychopaths, In Bruges) achieves this difficult tonal balance. He respects his audience’s ability to distinguish between the serious subject matter and the irreverent lens through which it is partially filtered, mostly through the eccentric interactions between the film’s many engaging characters. What could have been a more conventional drama instead becomes a challenging character study, eliciting our sympathy and stoking our frustration in equal measure.

Three Billboards centres on Mildred Hayes (Frances McDormand), a gift shop clerk who is fed up with the unfinished investigation into her daughter’s death by the local police. As a result, she rents out three billboards by a turnpike near her home that accuse the police chief of neglect. Her initiative incites more anger than compassion, due to the townsfolk’s respect for Chief Willoughby (Woody Harrelson), who struggles with private and public issues of his own. What is abject failure in her eyes is a disappointing conclusion in his, a regrettable but necessary end to a tragic case.

The ensemble performances are excellent, highlighting the range of each and every actor that is demanded by the unique presentation of the material. Frances McDormand can deliver sharp rebukes as well as she can quietly monologue and act physically, making us laugh uncomfortably and ache for her in equal measure. Sam Rockwell is captivating as a childish and unstable deputy, with a propensity for violence and hate despite his opportunities for civility and compassion. Woody Harrelson delivers an excellent interpretation of Willoughby when he could have easily been the villain; instead, he is a figure mired in controversy, and we are encouraged to wonder whether his efforts were enough.

The brilliance of McDonagh’s screenplay lies in its goal to challenge our perception of its characters as protagonists or antagonists, as “good” or “evil” individuals. It is certainly a pitch-black tragicomedy, but it is also an affecting exploration of why people act the way they do, without endorsing their actions. They are presented as profoundly flawed and complicated people, whose decisions have repercussions with the possibility, but not the guarantee of redemption. Mildred, Officer Dixon (Rockwell), and Willoughby could all have been written and performed as easy tropes (the grieving mother, the psychotic underling, the incompetent officer), but they are fleshed out in such a way that they cannot be defined by such easy descriptors. Three Billboards Outside Ebbing, Missouri is an excellent achievement in tone and character work, portraying a collection of different people as they attempt to navigate the aftermath of a horrific event.