In the 1980s, Eleanor Douglas isn’t just the new girl on the bus. She’s the new girl who is readjusting to life at home with her impoverished family — trying to evade the notice of her abusive stepfather and struggling with body-image issues. Steve, Tina and the rest of the kids at the back of the bus don’t let Eleanor sit down. In a fleeting moment of pity, Park reluctantly allows her to share his seat.
At first, Park is appalled by Eleanor’s loud taste in clothing and wonders why she doesn’t try harder to blend in. Eleanor mentally refers to Park as “the stupid Asian kid” because Park is half Korean. They sit beside each other every day without speaking. When Park realizes that Eleanor is reading his comics over his shoulder, he opens them wider and checks to make sure she’s finished reading before he turns the page. Then, still without talking, he begins loaning them to her, whole stacks at a time.
One morning when Park oversleeps and forgets to bring the comics, they talk about music. He makes her a tape of some of his favorite songs, and when Eleanor admits she has no way of listening to it, he lets her use his Walkman on the bus and loans her batteries so she can listen at home.
Riding the bus with Park becomes the one bright spot in Eleanor’s day. At school she has two girlfriends but is otherwise teased and bullied. Someone keeps writing sexual one-liners on her schoolbooks, and she returns to her locker after gym class one day to find it covered in maxi pads. Park tries to visit Eleanor at home to give her a comic book, but this gets Eleanor in trouble with her mom and her stepfather, Richie, and she is forbidden to see Park (or any other boy). She continues to avoid Richie as much as possible, a difficult task in a house with no bathroom door and a single bedroom that Eleanor shares with her four younger siblings.
Park keeps mixing tapes for Eleanor, and the two begin holding hands on the bus. When Eleanor baby-sits one night for her biological father, she takes advantage of having access to a phone and calls Park. He tells her he loves her, but Eleanor never replies because her dad and his fiancée arrive home.
Eleanor finally takes Park up on his offer to go to his house after school but is nervous around his picture-perfect family. Steve and his friends make fun of Eleanor on the bus, so Park fights him and gets grounded by his parents. At Eleanor’s house, tensions between Richie and Eleanor escalate when Eleanor uses a neighbor’s phone to call the police because she heard gunshots.
Eleanor and Park get into an argument before Christmas vacation, and they don’t see each other until Christmas Eve, when they sneak out at night to apologize and share kisses until the cold drives them back to their respective homes. On Christmas day, a drunken Richie throws a fit because there is no pumpkin pie. He drives away, leaving Eleanor’s family to salvage rice pudding off the floor for dessert.
While Park’s home life is much simpler by comparison, it is by no means perfect. His mother is polite but doesn’t understand what he sees in Eleanor, and his father is angry with him for not learning how to drive vehicles with a standard transmission. The two have never been close, as Park’s younger brother, Josh, comes much closer to their father’s athletic, all-American ideal of a perfect son. Their relationship only worsens when Park begins wearing black eyeliner and messy hair to school.
When Eleanor’s siblings learn that Eleanor has a boyfriend, she knows it’s only a matter of time before her mom and Richie find out. One day after gym class, Eleanor finds her clothing thrown into the toilet. She is forced to walk down the hallway wearing her too-tight gym suit and carrying her sopping clothes. Park sees her. Eleanor is embarrassed, but Park is very attracted to her. Later, when his family is away at a boat show, the two make out on Park’s couch. Later, they go on a date and make out in the back seat of the car.
After this date, Eleanor finds that Richie has destroyed all of her possessions and has left her a threatening note. She realizes from the handwriting that he is the one who has been writing all the sexual notes on her school books. She escapes through her bedroom window and flees into the night. Richie follows her in his pickup truck.
Unsure of where to go, Eleanor finds unlikely allies in Tina and Steve, the kids from the back of the bus. They hide her in Steve’s garage until they can deliver her safely to Park’s house. Park asks his parents’ permission to drive Eleanor to her aunt and uncle’s house in Minnesota, where she will be safe. Park’s father agrees and even gives him gas money for the trip but stipulates that he has to drive the standard truck instead of the automatic car. Park agrees and drives for several hours. Then he pulls onto a country road to get some sleep.
When Eleanor and Park wake up, they start making out. Eleanor wants to go all the way. But Park tells Eleanor that they have to stop. He needs to believe that this won’t be their last chance. When Park finally delivers Eleanor to her relatives’ house in St. Paul, she tells him to leave without coming in. They kiss goodbye. Park tells her he loves her and asks her to promise to call him that night. But Eleanor doesn’t call. He writes every day, but she never writes back. A year goes by. The rest of Eleanor’s family, without Richie, moves away, and Park gives up expecting to hear from Eleanor. Then one day, a postcard arrives from Eleanor, but the book doesn’t clearly state what it says other than that the message is three words.