Teeth

Dawn O'Keefe, a teenage spokesperson for The Promise, overhears her stepbrother Brad arguing with Melanie about sex and his reluctance to engage in vaginal intercourse. The argument exposes tense family dynamics and hints at how sexuality will shape the characters' choices throughout the story.

At a Promise group meeting, Dawn is introduced to Tobey and soon finds herself drawn to him within a circle that includes Gwen and Phil. The group agrees not to spend time alone together, creating a wary dynamic around their budding attraction.

Dawn and Tobey join the others for a day at a local swimming hole and later retreat to a cave to get warm. Dawn grows uncomfortable as Tobey becomes aggressive, and when she tries to leave, he uses force; she escapes the assault unharmed but shaken.

After a Promise meeting, Dawn encounters Ryan at a dance and declines a date, then returns to the pool and begins researching vagina dentata. She visits a gynecologist, where the examination turns coercive; Dawn defends herself and the doctor is injured.

That evening, police cars pass by as Dawn heads home, and later Tobey's body is recovered at the pool area.

Back at home, Dawn finds her mother Kim unconscious while Brad and Melanie are in Brad's room; Kim is rushed to the hospital.

Dawn seeks help from Ryan, who uses soothing talk to calm her, and their interaction reveals manipulation on his part. The next morning, Ryan's bragging about pressuring her into sex intensifies Dawn's anger.

Dawn's anger at Ryan's manipulation culminates in a violent moment in which Ryan is harmed during their encounter and dies.

Brad tries to consolidate control over the house while Bill attempts to remove him; Brad retaliates by letting his Rottweiler threaten Bill, revealing his possessiveness toward Dawn.

Dawn meets Bill and Melanie at the hospital after her mother dies, and Melanie recounts how Brad told her to ignore Dawn's mother's pleas. Dawn's resolve to seek revenge hardens.

Returning home, Dawn confronts Brad in his room; the encounter ends with Brad harmed and soon dead, underscoring the film's theme of revenge. The dog scene underscores the chaos surrounding the events.

Dawn cycles away from the house with a punctured tire and accepts a lift from an old man. She falls asleep in the car, wakes outside a convenience store at night, and the old man’s unsettling gaze lingers as she offers a sly, ambiguous smile.