Millie Colloway's life takes a dramatic turn when she becomes a housemaid, helping other women flee abusive marriages with the help of her ex-boyfriend, Enzo. Millie lives a comfortable life while continuing her studies at a community college. Her boyfriend is a lawyer who knows nothing of her past. The following year, Millie loses her babysitting job, but she soon finds employment as a housemaid in Douglas Garrick's penthouse, Coinstock's CEO. Upon starting her new job, Millie notices suspicious behavior as Douglas's wife, Wendy, never emerges from the guest bedroom. Concerned for Wendy's safety, Millie discovers evidence of abuse and agrees to help her escape. With Enzo's assistance, Millie orchestrates Wendy's escape to stay with a school friend.
However, Wendy is eventually brought back by Douglas, leading to Millie's dismissal from her job. When Wendy reveals Douglas's violent tendencies and shows Millie a loaded revolver, Millie advises against using violence. On her final day at the penthouse, Millie witnesses Douglas strangling Wendy. In a desperate attempt to save her, Millie uses the gun, resulting in Douglas's death. Wendy tells Millie to leave because she doesn't want her to get involved in the mess.
Afterward, the police come to interrogate Millie the next day, charging her with Douglas's murder. They inform her that Wendy accused her of killing her husband because he wanted to end their relationship. Millie calls Brock to act as her lawyer, but he leaves in the middle of the interrogation when the police present evidence of Millie having an affair with Douglas. She then realizes that the person she shot wasn't Douglas. Meanwhile, Wendy and her boyfriend, Russell, celebrate the success of their plan. The police do not arrest Millie due to lack of evidence, but she understands that the main culprit is Wendy. She uses Wendy to fulfill her ulterior motives and kills an innocent person. In the end, Millie devises a plan to take revenge on Wendy with Enzo and Russell's wife, Marybeth.
