Ari Aster, the director behind the horror films “Hereditary” and Midsommar,” is no stranger to upsetting an audience. But with his new movie “Eddington,” which premiered Friday at the Cannes Film Festival, Aster may have devised his most harrowing cinematic experience yet: forcing us to relive 2020.

Set in May of that year, the film chronicles a clash in the fictional New Mexico town of Eddington between the conservative sheriff, Joe Cross (Joaquin Phoenix), and the liberal mayor, Ted Garcia (Pedro Pascal), after the latter insists on mask mandates and lockdowns during the pandemic. “There is no Covid in Eddington,” insists Cross as he refuses to wear a mask, though his mounting frustration with Garcia may also have something to do with the mayor’s complicated romantic past with Cross’s wife (Emma Stone).

To bring his enemy down a peg, Cross decides to mount his own mayoral campaign, plastering his cop car with misspelled banners (“Your Being Manipulated”) and spouting conspiracy theories about his opponent that he posts online. But as Eddington erupts in Black Lives Matter protests and teenage activists begin training their phone camera on Cross, hoping to catch him in an act of police brutality, the escalating tensions in this small town threaten to claim to lives right and left.