The movie starts off with a sister that ends her life and her parents, in a very weird, hose incident. A couple travel to Sweden to visit their friend’s rural hometown for its fabled midsummer festival, but what begins as an idyllic retreat quickly devolves into an increasingly violent and bizarre competition at the hands of a pagan cult.
I’m not sure I understand. The name of your movie is the title of your post: “Midsommar.”
It definitely sounds like Midsommar (2019) https://www.imdb.com/title/tt8772262/
but there is also Midsommar (2003) https://www.imdb.com/title/tt0339385/ which has a very similar plot and was remade as Solsitce (2007) https://www.imdb.com/title/tt0473267/