Kindred Spirits (2019)

Chloe, a single mother in a relationship with Alex, has her life turned upside down when her younger sister, Sadie, comes home after a long, unexplained absence.

Though Sadie seems to want to settle in with her sister and 17-year-old niece (becoming quite a handful herself), she's actually a deeply disturbed young woman who has a sinister agenda regarding anyone who gets between her and her big sister.