Madhouse (1981)

Overview

As their birthday approaches, a woman finds herself in a terrifying game of cat and mouse with her psychotic twin sister, who is determined to kill her. The tension escalates as the sister's violent tendencies resurface, turning their once-celebratory occasion into a fight for survival. With each passing day, the woman must navigate the chilling reality of her sister's madness, all while trying to uncover the dark secrets that bind them. Will she unravel the truth before it’s too late, or will her twin's deadly obsession claim her life?