Midsommar

In the middle of winter, an American student, Dani, is traumatized after her sister Terri, who has bipolar disorder, kills their parents and herself via carbon monoxide poisoning in a murder-suicide. This strains Dani's relationship with her already increasingly distant boyfriend, Christian.

Several months later, Christian and his friends Mark and Josh have been invited by their Swedish friend Pelle to attend a nine-day midsummer festival at his ancestral commune, the Hårga, in the rural Hälsingland region of Sweden. The festival occurs only once every 90 years. Josh, writing his thesis on European midsummer festivities, regards it as a once-in-a-lifetime opportunity. Christian had intended to break up with Dani, who is still grieving the death of her family, but reluctantly invites her after an argument.

At the commune, they meet Simon and Connie, a British couple who were invited by Pelle's commune-brother Ingemar. Ingemar offers the group psychedelic mushrooms. Dani has a bad trip and hallucinates about her dead family. The day after their arrival, the group witnesses an ättestupa ceremony, whereby two elders commit suicide by jumping off a cliff onto the rocks below. When one of the elders survives, the commune members mimic his wails of pain before crushing his head with a mallet. The commune elder, Siv, attempts to calm Connie and Simon by explaining that every member does this at the age of 72.