The movie Mommy Be Mine follows the story of a 16-year-old girl named Lianne, who is a psycho killer and is haunted by the memory of her dead mother, whom she adored. Lianne's father, who is an alcoholic, blames her for his wife's death and neglects her, leading Lianne to seek out her mother's love and attention in some other way.
Lianne soon becomes fixated on a new girl, named Rachel, who arrives in town and has similarities to her mother. Lianne is convinced that Rachel is the one who can replace her mother's love and affection, and she'll stop at nothing to be close to Rachel. But when Rachel starts to understand Lianne's obsession, she tries to distance herself, causing Lianne's behavior to become increasingly erratic and dangerous.
As Lianne's psychotic tendencies escalate, Rachel's life becomes threatened, and her family starts to fear for her safety. Lianne's father realizes he needs to intervene before it's too late and enlists the help of a therapist to try and change his daughter's behavior. However, Lianne's erratic and violent behavior makes it difficult for anyone to help her, leading to a dramatic and violent ending.
