After her parents die in a fire, Dani Ardor (Florence Pugh) decides to end things with her boyfriend Christian Hughes (Jack Reynor). However, she’s stopped by her bipolar sister Terri, who leaves a cryptic message. Dani soon learns from her commune-brother Pelle that they will be going to Sweden to celebrate the “midsommar” festival at the Harga village where he grew up. Josh wants to go as well because he wants to write an anthropology dissertation about the place.

Once at the commune, they meet Pelle’s brother Ingemar and a British couple named Simon and Connie. The group takes psychedelic mushrooms, and Dani experiences a bad trip in which she hallucinates about her dead family members.

On the second day, they witness attestupa, where two elders jump from a cliff onto rocks below. One of the elders survives but is crushed by a massive rock. The other elder is killed by Blood Eagle while attempting to flee, and obnoxious womanizer Mark is also put through the same thing.

During the final ritual, the community must offer nine human sacrifices. The first four — Mark, Josh, Simon, and Connie — are outsiders who were lured there by Pelle and Ingemar, while the other four — paralyzed Christian in a disemboweled bear, and Ingemar and Ulf — are commune members. Dani is crowned May Queen and chooses her boyfriend to be the final sacrifice. The cult stuffs him inside the bear’s body, which is then burned along with Dani and the other five.