That Girl (2018)

Self-centred party girl Ashley relies on her sensible flat-mate Becca but masks her dismay when Becca announces her intention to move in with boyfriend Sam, who dislikes Ashley. Unbeknown to the couple Ashley stalks a young man from her past and, high on drugs, pulls a knife on him. When she explains her motive to her friend this leads Becca to an admission and a decision.