A teen girl held prisoner in her own cellar is forced to take matters into her own hands when her deranged captor targets her family.

Having escaped a crazed Travis, Missy flees through the woods in hopes of finding someone to help her. She is unable to yell for help due to her vocal cords being surgically severed. When she spots two campers unaware of her presence, she has hope until Travis arrives and makes sure she can never ask for help again.

Maisie Allen is a vibrant senior happy with her life until her parents move her out of the city. Her younger brother Wyatt accepts the move and challenges that come with it. Their mom, Mia, and their dad, Luke, give each a house key so they can get in after school. Maisie is careless with hers and has it stolen by Travis, who targets her as his next victim. He follows Maisie home and puts his master plan into place.

The first time Maisie is home alone, Travis strikes. He injects her with drugs and performs surgery on her vocal cords to keep her from screaming for help while held prisoner in her own cellar. Chained to a cot, Maisie is forced to converse with her captor using a whiteboard.

Travis has cleverly made it appear that Maisie has run away from home so the police barely search for her. He sets up cameras in the house and roams free when the family is gone. While looking for supplies in the attic one night, he comes face-to-face with Luke at the top of the steps. Seeing the value of having one less person to hide from, Travis pushes Luke down the steps to his death. 

A tomboyish detective, Anna, stops by to see what’s going on and takes an interest in Mia. While they become friendly, evidence starts to build against Mia that she may not be innocent in the back-to-back events.

When a nosy neighbor discovers Maisie is home, Travis kills her. With two deaths and a disappearance surrounding Mia, Anna is forced to bring Mia in for questioning. In the meantime, Wyatt has run off from his new day camp and goes home, catching Travis by surprise. Travis takes him prisoner and tries to mastermind a plan of getting rid of him.

Mia discovers the hidden camera in the kitchen, then the trap door concealed underneath a rug. Travis takes her prisoner as well and attempts to poison her, only she outsmarts him and puts up a fierce fight for the sake of her kids. About to lose the battle, Maisie comes to the rescue and ends Travis’s reign of terror.

After surgery to repair her vocal cords, Maisie shows promise that she can make a full recovery from the ordeal and be a normal teen again.