Movie opens with a closeup of Dot (Camilla Belle), a deaf/mute high-schooler as her voiceover describes the more people in the room the more invisible she felt.
Dot is sitting alone in a crowded cafeteria. At a table across from her, her new god-sister, Nina Deer (Elisha Cuthbert) and Nina's best friend Michelle (Katy Mixon) are loudly discussing Michelle's desire to have sex with a classmate/friend, Connor (Shawn Ashmore), who walks by. Nina notices Dot watching them and angrily snaps at Dot, who turns away, as Michelle playfully chides Nina for having a loser "freak" move into the family. A guidance counselor, Mrs. Feltswatter, asks Dot if she could join her at the table, at which Dot just ups and leaves. She retreats to her favorite hiding spot, a stall in the girl's bathroom, until Nina finds her and angrily pulls her out for the ride home.
Back at the expansive, but cold and incompletely decorated, Deer home. Nina's mom and Dot's godmother, Olivia (Edie Falco), is preparing dinner and implores Nina and Michelle to try and accept Dot, who is sitting over at the table in the dining area, into the family. Nina retorts it wasn't her decision to take her in and insults Dot, who is oblivious to the conversation. Olivia reminds Nina that Dot can read lips. We learn that Olivia is an interior designer and Nina's dad and Dot's godfather, Paul (Martin Donovan), is a successful architect.
Paul is at a pharmacy picking up prescription painkillers for Olivia when he bumps into Mrs. Feltswatter, the guidance counselor. She expresses concern that Dot is unhappy at school, and Paul informs her that Dot is living with them now and that her father had just died and her mother died ten years ago.
Paul arrives home with the painkillers and greets the girls. Nina is finishing up cooking dinner and informs him that Olivia is passed out (sleeping) in the living room. He makes an irritated face and goes to get her. When he leaves, Nina grabs some painkiller pills from the bag and tries to get Dot to take some. She ignores Nina, who calls her an expletive and proceeds to down the painkillers herself.
Meanwhile, Paul collects Olivia from the unfinished living room floor and puts her to bed, where he gives her some painkillers. Paul gives her a look while she's downing them and she insists they're for her hip pain. There is obvious tension between the two as she angrily points out that he thinks she's always doped up and doesn't do anything for the family.
Back at the dinner table with Dot & Nina, Paul mentions it might be a good idea for them to go to some sign-language courses. Nina blows off the suggestion and says she can't believe Dot is staying, to her Dad's dismay. She then goes out, telling her Dad he should use the time to bond with his "new daughter".
Next day at school, Dot gets paired up with Connor during a piglet dissection in science class. She ignores him, while she slashes away at the dead pig.
In the cafeteria, Michelle is complaining to Nina and another cheerleader friend, Fiona, about the pairing of Connor and Dot as lab partners. The conversation turns to Nina, where she's goaded for still being a 17-year old virgin when she can have any guy she wants. Michelle makes fun of Dot at the other table, as she converses in sign language with one of the lunch ladies who has a deaf daughter.
Dot is walking the school halls when she notices a piano in the empty music room. She enters and begins playing some slow Beethoven, while doing a voiceover about how Beethoven discovered he was going deaf and managed to continue to be inspired. Meanwhile Connor is walking by with his friend Brian and some others and notices Dot playing through the door window and begins to find himself attracted to her. He quickly pulls away when his friends want to see what he's looking at.
Dot heads to off to the bathroom to hide out but bumps into Nina who's applying makeup there. Dot reluctantly allows Nina to put some lipstick on her, as Nina says she feels bad that they stopped seeing each other after Dot's mom died and if Dot had had some female influence while growing up she "wouldn't look like a janitor all the time". She leaves and Dot looks in the mirror to see that Nina had purposely smeared the lipstick all around her mouth like a clown.
In her bedroom, unable to sleep, Dot pulls out a box that contains her father's ashes. Through her voiceover we discover that her father was deaf and was recently hit by a truck he couldn't hear and killed. This happened while Dot was with him at a restaurant and he went out to run across the street to a bank. She places some of the ashes on her fingers and then tastes them and places some on her face. She moves to the bathroom to wash it off, as she mentions that she may have been able to save him if she was with him.
On the way back to her room, she notices Nina's bedroom door has opened a little and she peeks in and sees Nina and her Dad in bed together, and we hear him sweet talking her. Dot heads back to her bedroom, obviously disturbed, but she keeps it to herself.
At the dinner table with Nina, Dot, Paul & Olivia, Nina says she's spending the night at Michelle's. Paul says she can't go since it's a school night. She pleads with her Mom, who questions why she can't go which prompts Paul to snap at her for always contradicting him. Nina then rubs his leg under the table with hers and says she finished all her homework. Her Mom says it's up to Paul, who doesn't answer now, so she gets up and leaves to go out when Michelle calls her cell. Paul gets up and has an argument with Olivia in the kitchen about undermining his authority in raising Nina and storms off. Olivia talks to Dot about her mother, who she was friends with in school, and calls her a "big, old, lucky slut" who didn't marry the first guy she went out with, unlike her and Paul.
In the living room, Olivia is flipping through a patterns book and Dot hands her a note asking to go to the movies. Olivia says sure, but Paul overhears, and says she's in no condition to drive and he would drive her. In the car, Dot is obviously now uncomfortable being alone with Paul.
In the near-empty movie theater Dot takes a spot up in the back row alone. Nina, Michelle, Fiona, Connor and Brian happen to come into the same theater and sit toward the bottom. Connor notices Dot, and asks if they should invite her to sit with them, where it's met with vehement disagreement from the others. Fiona remarks how screwed up it must be to never have heard anything. Nina says Dot was able to hear until around the time her Mom died when she was seven, and how it was probably worse to have lost it than never to have heard in the first place. As the movie begins playing Nina, begins inconspicuously covering her ears to see what it's like to be deaf, but stops when she sees Dot staring down at her.
Back at Michelle's, she and Nina are on Michelle's bed watching a scene of two people passionately kissing. Michelle asks Nina how you would know if you were a bad kisser, to which Nina doesn't know the answer to. Michelle suggests the only way would be kiss someone you really trust and ask them how it was. This advance by Michelle goes right by Nina who is engrossed in the movie.
Dot still unable to sleep, sees Paul coming down the stairs. She fakes sleeping as Paul enters her room. Thinking she's asleep, he sits on her bed, and as he's stroking her hair, he whispers to her that he's sick and that he thought things might change when she came to live with them. He says, "I hate it here" and leaves.
Back to Michelle's bedroom, she asks Nina if there was one place you could go where would it be. She replies Australia because it's really far away.
Next day at the cafeteria, Dot is alone at her table again. Connor, Brian, Michelle & Nina are at the table across from her. They are discussing plans where Brian's parents are going away and he'll have a small party, with drinks for all. Michelle suggests Nina can sneak out and snag some drugs from her mom, since she's a "prescriptoholic." Nina is not amused and is not sure she can come, but Michelle goads her, as she sees this as a chance to get to sleep with Connor.
Dot is alone at home playing some classical piece on the piano in the main room. Unbeknownst to Dot, Nina comes home, hears the music and is quietly listening to it in the doorway. While playing, a piano wire suddenly snaps and Dot curses out loud, startling Nina who quickly ducks around the corner. Dot begins to try to find the damaged piano key by tuning along with her voice to the keys, with Nina all the while listening to this, now knowing that Dot's deafness is not at all as it seems. She sneaks back to the door, slams it as if she just came in and greets Dot, who has now stopped playing, without letting on about what she just witnessed.
At the cafeteria the next day, Nina, goes over to Dot's table, who is as usual alone, and pulls a chair right up next to Dot. While Dot is eating her sandwich and staring straight ahead, supposedly ignoring Nina, Nina talks directly and angrily into her ear how much she hated her, the love\hate relationship with her own Dad with all the lurid details of their incestuous encounters and her plans to kill him in the middle of the night with a gun (supplied by Michelle, who will steal it from her Dad) while Mom is drugged out and Dot "can't hear". We can see that Dot is disturbed by these confessions, but she keeps her reactions in check. Angry that she couldn't goad a response out of Dot, Nina storms off.
Dot is back at the school piano again, when she notices Connor watching her through the door. Connor stops her as she tries to leave and tries to set up a date where they can work on the lab report together. She pulls the already completed report out of her bag, gives it to him and leaves to his dismay.
While the Deers are at the dinner table, Connor stops by and surprises Nina who was expecting Michelle. He asks if Dot can come to the library to go over the lab report. Meanwhile Michelle arrives for the secret party with a brown bag and gives it to Nina. Dot notices the bag and is visibly affected. Nina notices and rhetorically asks Dot what she's looking at, at which Dot gets up and leaves with Connor.
Dot and Connor are at a diner. He starts off with small talk about the lab report, but eventually begins confessing things about himself and his feelings towards Dot, including asking if she's a virgin like him. She does not respond or acknowledge. Meanwhile Nina and Michelle are up in her room, discussing nipples, when Paul comes up and tells her to send Michelle home because it's a school night. Nina tells her she can't come to the party and Michelle leaves angry.
Dot sees an ambulance drive by at the diner and rushes home where she finds the bag Michelle brought over sitting on a chair in the dining room. She opens it and finds it not to contain a gun, but instead porn DVD's. She sneaks over to Nina's room where she discovers Nina and her dad about to have sex. She breaks a statue against the wall to break it up. Nina, taken off guard, comes out and helps her clean it up, while Paul emerges and tells her to be more careful around the house. He goes back to his bedroom where he tries to say something to Olivia, but she is faking being asleep.
Nina is back in her bed crying, and she thinks her Dad is coming back in so she says she's tired, but it's Dot, who gets into the bed and puts her arm around Nina to comfort her as she goes to sleep.
The next morning Dot is still in Nina's room and Nina is ironing her cheerleader outfit, at which point she infers to Dot that midnight tonight will be the night she kills her dad for sure with the iron, burns the face off a teddy bear for effect and throws it to Dot. She is still unaware that Nina knows she is not deaf, and Nina tells her it's a good thing she's deaf because she could be considered an accomplice.
At night, outside the school gymnasium where Connor is playing in a basketball game, Dot dials Child Welfare on a pay phone, but decides to hang up when someone answers. She enters the gymnasium and watches the game where Connor is playing so bad he gets benched. Nina, Michele and Fiona are there as part of the cheerleading squad.
After the game, Dot stops Connor and pulls him into the empty and darkened school swimming pool building. Connor is talking to Dot by the pool about going on road trips with her and how quiet it would be, but when she's not looking he's confessing about how many times he masturbates and how he's a sex addict, who sucks at basketball.
Meanwhile, back in Paul & Olivia's bedroom, she pops some more pills and mentions to Paul that Connor would be a cute guy for Nina. Paul gets mad and tells her to be careful about pushing her into dating and dressing like a slut. She comes out of the master bathroom and disrobes asking Paul if she's getting fat. Paul emphatically ignores her advances and gets into bed to go to sleep. Olivia calls him mean and says she's sleeping on the floor. Paul tells her to get into bed, but she refuses so he picks her up and throws her onto the bed and he goes downstairs.
Back at the pool, Connor and Dot have gotten closer and while she's not looking he is confessing to her how he has kissed lots of girls but has never "done it", at which point she sits up, and to Connor's surprise, takes her shirt off, does the same for him, and they begin to kiss.
Back at the Deer house Nina comes home alone and encounters her Dad who is eating ice cream in the kitchen. He tells her he has a present for her and gives her an expensive pocketbook after which he makes advances toward her. She stops him, removes her cheerleader dress and tells him she'll be in her bedroom.
Back at the school, Connor and Dot are having sex poolside, though she doesn't seem to be enjoying it. When it's over she notices the clock nearing midnight so she rushes back to the house.
Back the Deer house, Paul quietly took a candle out of the bedside table and headed back to Nina's room, though we see that Olivia is definitely awake. Nina is ironing her skirt to put it away, while holding off her Dad's advances. She tells him she has a surprise for him and to sit on the bed with his eyes closed. He does so and she walks up to him and is about to ram the hot iron into his face when Dot comes home and slams the front door. Dot listens by the door. Nina chickens out and ends up telling her dad that she's pregnant with his child. He gets upset and asks if she's sure and what's she's going to do about it. Nina gets mad and says she doesn't want a baby with webbed feet running around the house and needs $1000 cash tomorrow to get an abortion. He agrees and leaves.
Nina goes to Dot's room, gets into bed with her and confesses that she's wasn't brave enough to do it.
At the lunch line in the cafeteria the next day Connor asks Dot to go to the Spring Fling dance with him, via translation from the lunch lady. Dot says no and that she's wrong for him and she needs to be by herself and leaves. Michelle and Nina, who were in the same line witness it and Michelle begins to curse out Dot, when Nina cuts her off and tells her to back off.
Back in Dot's room that night, Nina brings her a dress for the dance to try to get her to go and confesses to Dot that she will be taking the $1000 and running off to get started in Connecticut where she can be a stripper and makes lots of money and even become famous like Courtney Love, who was one. She says it was so hard lying about being pregnant that part of her thinks it's true. She puts the lipstick on Dot again, but this time it's perfectly applied and leaves to get ready.
In the bathroom, Dot is holding the dress up to herself to see how it looks in the mirror. Nina comes in and Dot begins to wipe off the lipstick and puts down the dress. She's not going. Nina asks Dot to let her in on her secret, but she walks away.
Olivia is downstairs in the dark staring at the blank walls. Dot is downstairs playing Moonlight Sonata on the piano. Nina sneaks into her parents bedroom to steal some of her mom's pills and finishes getting ready in the master bedroom. Meanwhile Paul is looking for Nina and notices tampons in her new bag. He grabs the bag and begins badgering Nina in the bedroom about the "pregnancy". He then confronts Nina about the tampons where she at first says they belonged to Michelle and she was holding them for her since she had no bag. He doesn't buy it, throws the $1000 at Nina and calls her a whore. He begins slapping Nina around and then begins to force himself on her. Olivia hears all this and is crying downstairs, but does nothing. Dot hears, stops playing and rips out a piano wire. She heads upstairs, comes up behind Paul and strangles him with it, while screaming for him to leave Nina alone. Nina drops to the body screaming at Dot for killing her Daddy. Olivia comes upstairs in a daze and says it's a miracle that Dot can speak.
Michelle and Fiona show up to pick up Nina for the dance and Dot tells Nina that they have to bury the backpack (presumably with their bloody clothes in it). Dot goes to the dance with them, but gets intercepted there by Connor who makes her dance with him. Nina takes the backpack and hides in the bathroom stall with it.
Meanwhile, we see Olivia sitting in the bedroom, contemplating, with Paul's bloody body at her feet.
Dot leaves Connor abruptly on the dance floor and he follows her out. He calls out for her to wait and when she stops with her back to him, he knows now that she can hear and tells her to turn around. Obviously distressed, he berates her for actually hearing his dirty secrets, calls her a psycho and tells her to shove off, as she tries to apologize to him.
She continues on to collect Nina from the bathroom and they run out through the woods to a creek where they bury the backpack. Nina asked why Dot pretended to be deaf all this time and she replied she wanted to be closer to her father and farther from everyone else. They head back home walking through the creek.
When they arrive back at the house police are everywhere, and they are leading Nina's mom out in handcuffs. They run up to her and Olivia tells Nina that she did a terrible thing in that she killed her father when he started going crazy, breaking things and saying he hated her, so she took a piano wire and strangled him with it. She tells Nina she never wanted him to hurt her and if she could ever forgive her, as they take her away in the police car.
Fade to the piano in the house during the day where Nina is tentatively playing on it. Dot comes up and joins her as the camera pulls away from them.
Nina used to think she would not even have a funeral....and now, with her Daddy/tormentor dead, she has a chance at life....