Following the tragic and accidental death of her deaf father, Dot, an orphaned teenager who is deaf-mute, is forced to move to Meriden, Connecticut, where she will stay with her godparents, Paul Deer and Olivia Deer, along with their teenage daughter, Nina. Once childhood friends, Dot and Nina's relationship has soured; Nina now harbors resentment towards Dot, regarding her arrival as an infringement. Dot quickly becomes aware that Olivia, who used to be close to Dot's mother, is struggling with alcoholism and a prescription drug addiction, further complicating their home dynamic.
One fateful night, while Dot silently navigates the house, she inadvertently witnesses a shocking encounter between Paul and Nina, revealing their inappropriate and long-standing incestuous relationship. This disturbing truth illustrates Nina's manipulation of her father, using their illicit bond to fulfill her desires.
At school, Dot feels completely isolated among her peers until she catches the attention of Connor, a basketball player, which irks Nina and her aggressive friend, Michelle. After one cheerleading practice, Nina discovers Dot playing Beethoven on the piano, and when a string snaps, Dot's exclamation reveals her ability to hear and speak. Seizing this knowledge, Nina pretends that Dot is deaf, exploiting her secret to confess her intense hatred for her father and a chilling plan to murder him.
The tension builds as Dot goes out with Connor, who communicates with her through lip reading. Upon returning from their date, Dot disrupts another secretive rendezvous between Paul and Nina, indicating her tacit support for Nina’s endeavors. As a deep trust forms between the two girls, a troubling situation escalates—Nina confesses her intent to kill Paul, driven by her desperate quest for freedom and a twisted hope of starting anew.
As prom night approaches, Nina plans to commit the act, claiming she will use his money under the pretense of a pregnancy to escape with Dot. An argument erupts as Paul confronts Nina about her lies, leading to a confrontation filled with violence that culminates in an unimaginable act of desperation. Taking a stand for her friend, Dot intervenes, leading to a shocking twist; she strangles Paul with piano wire, revealing the lengths they will go to for freedom.
In a daze of bloodshed, Olivia stumbles upon the horrific scene, seemingly unaffected by the murder, only to be shocked that Dot can hear. The chaos continues as Nina and Dot quickly change out of their bloodied dresses before heading to the school dance, where Dot finally embraces her identity by revealing her ability to speak to Connor. However, the ensuing fallout after Connor's angry departure leads the girls to confide in one another on a riverbank, where they dispose of their stained clothes and grapple with the emotional turmoil of Dot’s silence after the death of her father.
Returning home, they find a police presence, as Olivia chooses to turn herself in for what occurred, igniting a moment of reconciliation with Nina. The night concludes with a powerful and bittersweet scene of Dot and Nina together at the piano, liberated from their troubled pasts.
