17-year-old aspiring rapper Elina is forced to move from Finland to southern France when her mother gets a French boyfriend. When she meets her new step-sister, the charismatic ballerina Sofia, who lives a double life full of drugs and alcohol, she immediately feels attracted. An infatuation that soon transitions into obsession while Elina adopts increasingly brutal methods to have her for herself, while Sofia pulls Elina deeper into her own world of lies and deceit.