Park is a half-Korean boy growing up in Omaha, Nebraska. In 1986, he is sixteen years old and struggling to fit in. One day he looks up during his morning bus ride to school, to discover that a large girl with red hair is trying to find a seat. He doesn't want to make a target of himself by offering, but allows her to sit by him. Over the coming weeks, they share a seat on the bus and gradually begin to share their thoughts about books and music. Park finds himself reading comics on the bus and allowing Eleanor to read over his shoulder.

Eleanor's situation at home is desperate. She has four younger siblings. A year earlier, she had argued with her stepfather, Richie, and he kicked her out of the house. Her mother left her with friends and it took a full year for her to bring Eleanor to their new home. Richie is always on the verge of an explosion and the rest of the family tries not to anger him. They are not always successful and violent fights are common.

Park's home life is vastly different. His father is hard on Park because he wants Park to be a different kind of teenager. Park's mother is petite and kind. Both love Park and want what's best for him.

Eleanor is picked on at school and Park comes to the point of wanting to protect her from the bullies. He gets in a fight one day and some of the tormenting slacks off. Someone continues to write sexually explicit words on her school books. She eventually reveals that Richie is the one writing on her books and it becomes clear that she is in danger of being molested if she remains at her mother's home.

Eleanor runs away from home but can't figure out how she can possibly get away from the danger Richie represents. Help comes unexpectedly from a teenaged girl named Tina who had been among those tormenting Eleanor. Tina realizes that the situation has turned dangerous for Eleanor and helps her hide. Tina and her boyfriend Steve contact Park and he knows he has to help her escape, even though he doesn't want them to be separated.

Eleanor has an uncle in Minnesota and she plans to hitchhike here. Park decides he will take his parents' car and drive Eleanor to her destination. He tries to sneak out of the house but his father intercepts him. Park explains he situation and his father agrees that he can go. He gives Park extra money and urges caution. He says that if Eleanor's uncle doesn't allow her to stay, Park is to bring Eleanor back to their house. He promises to help ensure that Eleanor is safe from the situation.

Eleanor's uncle does allow her to stay and provides more in security and material possessions than her mother had. Park writes to Eleanor, sometimes every day, but Eleanor doesn't write back. A year passes. Park gets a job and goes to the prom with another girl and is relieved that she is nothing like Eleanor. He eventually stops mailing the letters, but continues to write them. Then one day, Park's father enters the room and announces that Park has a postcard. It's from Eleanor and there are only three words written on the postcard.