Following the tragic and untimely death of her deaf father, Dot, an orphaned teenager who is both deaf and mute, is sent to live with her godparents, Paul Deer and Olivia Deer, in Meriden, Connecticut. They have a teenage daughter, Nina Deer, who once shared a close friendship with Dot during their childhood, before Dot lost her hearing due to a medical condition. However, upon Dot's arrival, she quickly realizes that the aloof and resentful Nina has no interest in rekindling their bond, often subjecting Dot to a barrage of insults and harsh treatment. The tension escalates as Dot observes that Olivia, an unfulfilled interior designer and former confidante of Dot's mother, struggles with alcoholism and a troubling prescription drug addiction, further complicating the household dynamics.
One fateful night, Dot inadvertently stumbles upon a shocking secret while returning to her room. She witnesses an intimate moment between Paul and Nina in Nina’s bedroom, revealing a long-hidden, incestuous affair that Nina has been using as leverage against her father for years to fulfill her selfish desires. Meanwhile, at school, Dot finds herself ostracized, yet a glimmer of hope arrives when Connor, a basketball player, shows interest in her. This development incites jealousy from Nina's abrasive friend, Michelle, who is also vying for Connor's attention.
The plot thickens when Nina unexpectedly interrupts Dot as she passionately plays Beethoven on the family piano, causing a string to snap. Nina hears Dot express frustration, causing her to reassess her perception of Dot’s abilities. A strategic act of manipulation unfolds as Nina feigns ignorance, later confessing her deep-seated hatred towards her father and revealing a chilling plan to murder him during lunch the next day, all while pretending that Dot remains deaf.
As events unfold, Dot goes on a date with Connor, allowing him to communicate through lip-reading, which fortifies their budding connection. However, upon returning home, she once again witnesses Paul and Nina's sordid entanglement, deliberately causing a ruckus to indicate her silent agreement with Nina. This alliance strengthens further when Dot comforts Nina as she weeps in her room. That evening, after a basketball game, Connor confides his personal struggles to Dot, and the two share a passionate encounter in the school swimming pool, marking a pivotal moment for Dot.
However, Nina's plotting continues as she escalates her plans to harm Paul. After another confrontation with her father, which the audience learns spirals into violence, Dot intervenes in a moment of fierce loyalty and bravery. In a whirlwind of chaos, using a piano wire, she strangles Paul to death, an act witnessed only by Olivia, who, in a drug-induced haze, reveals her shock upon discovering that Dot can, in fact, hear.
As the narrative progresses, Michelle arrives to pick the girls up for the school dance, a seemingly innocent event that becomes a convoluted mask for the violent realities they just faced. Quickly changing out of their blood-stained dresses, Dot and Nina head to the dance, where Dot bravely reveals her secret to Connor—her ability to hear and speak. His anger towards her deceit causes a rift between them.
In their ensuing escape, Nina and Dot find solace at a hidden riverbank, where they bury the remnants of a life stained by trauma and betrayal. In an intimate moment, Dot shares the reason for her silence, illustrating her profound connection to her father that was ultimately severed by her mother's passing. Upon returning home, they are confronted by the aftermath of their violent actions as police surround the house, leading to Olivia's confession and an apology to Nina for ignoring her suffering. Ultimately, the film culminates in a poignant moment of freedom as Dot and Nina take to the piano together, unshackled from the oppression of their fathers and the disarray that has haunted them.
