Eleanor Douglas is beginning 10th grade. She is the oldest in a family of two girls and three boys. All the children live with their mother and stepfather, Richie, in a tiny two-bedroom house. The children share one bedroom. There is one bathroom, and Richie has removed the door and will not allow a curtain for privacy. Richie is physically and emotionally abusive to the mother and often drunk. The children live in terror of him. Eleanor does not own a toothbrush or properly fitting clothes. She patches her clothes in bright colors, wears ribbons in her hair, and creates strange clothing combinations, over which her fellow students bully her. Eleanor has just returned after sleeping on the couch of a family friend since Richie threw her out a year earlier.
Park Sheridan has lived in Omaha his whole life. While his family is not affluent, and his parents come from very different backgrounds, his home is filled with love. While his father is tall and "masculine", Park takes after his mother in appearance and is shorter than his younger brother. Park believes he is a disappointment and is unenthusiastic about taekwondo, which his father values. Park is instead interested in alternative music and comics. He feels insecure about his size and Asian heritage, despite getting along with the popular kids at school.
On Eleanor's first day at her new school, the students find her weird. They rearrange their seats on the school bus to get her yelled at by the driver. When Eleanor is about to cry, Park rudely offers her a seat. They have a few classes together, during which Park notices Eleanor is one of the smartest students in class. They begin to connect.
Eleanor is bullied at school. Girls cover her gym locker with sanitary pads, and someone writes crude remarks in her school books. At home, Richie frequently screams at Eleanor's mother while drunk. One night, Eleanor hears gunshots and calls 911, but the police believes Richie's lies over her report. Eleanor tries to conceal her living situation from Park, but gets frustrated when he takes some things for granted, like a telephone, batteries, or safety. She tries to reject Park's gifts, believing herself unworthy. The two spend more time together in secret, since Richie won't allow Eleanor to have a boyfriend, and her mother and siblings' loyalties have shifted to Richie. Park professes his love for Eleanor, making her uncomfortable. Her first meeting with his parents does not go well.
Park gets into a fight with Steve, who was bullying Eleanor, and lands a taekwondo kick to Steve's mouth. Park's nose is broken in return. His mother grounds him "forever", thinking Eleanor is leading Park into trouble. Park's father, on the other hand, is proud of Park and understands that Richie is an abusive alcoholic. After seeing Eleanor's family, Park's mother invites Eleanor to stay at their house. Eleanor accepts and lies to her family about it. Eleanor's uncle offers to take Eleanor to Minnesota for the summer so she can attend a program for gifted teens. Richie says no.
One night, Park's mom tells the kids to go on a date. Eleanor returns home to a fight between Richie and her mother. She finds her personal possessions destroyed. She matches a hateful message written by Richie to the handwriting of the perverted notes in her school books. Eleanor flees and ends up in Steve's garage with him and Tina, who turn out to not be as bad as she had thought. She goes to Park's house and tries to formulate a way to get to St. Paul, Minnesota. Park insists upon driving her. His father sees him sneaking out of the house, but, surprisingly, gives Park money and tells him to take the truck. Park leaves Eleanor at her uncle's house. Eleanor's aunt and uncle welcome her and plan to remove her siblings as well.
Park sends Eleanor letters and gifts, but she does not respond. Park tries to forget her, but can't. Soon, Eleanor's siblings and mother disappear from Richie's house, leaving Richie alone once again. Park passes by Eleanor's former house frequently, longing for her. Park encounters Richie one day as he is coming back from one of his drinking binges. Park fantasizes about killing Richie, because he "can" and "should," but ends up only kicking the ground in front of Richie's face, who had fallen in the snow. Six months later, Park receives a postcard from Eleanor with three words on it.