After the death of her father, Marla Silk searches out her sister, who was shipped away to a home when they were both small children. She brings her sister - Irene - to live with her mother and two daughters. Their mother, Lollie, resents Irene's existence, telling stories about Irene's bloody birth and how their father was entranced by Irene, even though his wife almost died in the process of giving birth to her. Marla goes about her business as a workaholic lawyer who defends criminals and strikes fear into the hearts of those she challenges. One of the ways she discovers dirt to use against people is through two highly-trained, mysterious men who seem exceedingly loyal to her. When they are not doing business for her, they spend time chaperoning Irene. It comes out that Irene was sent away for being a violent child who attacked Marla, hitting her on the head with one of their mother's stilettos. Irene does not recall the incident and implies that their mother was involved in ways she does not admit. She notices that Lollie's attitude toward Irene changes over time, and Irene emerges as a cunning figure in a way that she does not know how to feel about. When Lollie shows up at Marla's office as her new paralegal, Marla is caught off guard. Lollie and her daughters paid her to finish high school and paralegal studies. Irene starts feeding Marla ways to take down her opponents in court, all while eerily dressing like her older sister.

During one particular case they are working on, Irene helps Marla build her case in favor of the rich Marcellus Bloom, who has a habit of beating up vulnerable women. Marla has had her two lackeys help him get away with it for years because he pays her. However, Marla becomes concerned when he starts trying to seduce Irene. She tries to protect her little sister, but her mother and Irene dismiss her concerns. Marcellus is a perfect gentleman, much to Irene's disappointment. Meanwhile, her two lackeys seem to have disappeared.

Marcellus tells both of them to meet him at a motel. Marla agrees. Irene and Marla meet him in a rundown motel, where he tells them there is no way out, and gently hits Marla twice. Irene offers herself to him and says they should kill Marla. She then proceeds to hit him in the head with the sharp heel of her shoe. They leave the hotel, and Marla's two lackeys show up, saying Marcellus delayed them. Returning home, the sisters put their regretful mother to bed. Marla talks about fleeing, though Irene is against the idea. At that moment, Marla felt a sensation in her own head as though Irene was hitting her, just as Irene supposedly did when they were children.