Dawn is a teenage spokesperson for a group called The Promise. She attends groups with a few of her friends. One evening after giving her speech talking about the ring of purity those in the group wear and what it means, she is introduced to Toby and finds him attractive.
The four begin going out as a group, and Dawn has fantasies of marrying Toby, although after acknowledging the attraction they agree that they cannot spend time together. Soon after they give in and meet at a local swimming hole. After swimming together, they go in to a cave to get warm and begin kissing. He then forces himself on her; in the panic her vagina bites off his penis. Horrified, he stumbles away and she flees the scene. After a Promise meeting, she meets a classmate at a dance; they talk, and he drops her off at her home.
Dawn researches female vagina mutations and realizes she vagina dentata, she visits a Gynecologist, Dr. Godfrey in an attempt to find out what is happening to her. After finding out that she is a virgin, he starts molesting her. She panics and her vagina bites off the fingers on his right hand. On her way back, she sees someone driving in Toby's car, and she goes back to visit the swimming hole. When she gets there she sees the police bringing up his body. At home, her ill mother has collapsed. Dawn's stepbrother, Brad and his girlfriend Melanie ignore her and continue to have sex while she lies on the floor. Kim is taken to the hospital.
She goes to a