Rowell's story begins with Eleanor at her first day of school, wearing men's clothes and hating herself for being what she believes to be fat and ugly. She is immediately made uncomfortable upon sitting on the bus and being stared at by everybody; none of the riders want her to sit beside him or her because every place is 'saved' for another individual. The driver was shouting at her to sit, and after an obnoxious passenger named Tina continuously refused to let Eleanor take a seat, Park told her to sit beside him.
Although the seating arrangement carried on for weeks, it was typically quiet between Eleanor and Park, but Park thought he would be able to soon start a conversation. He noticed that when he read his comics, Eleanor was reading them over his shoulder; his oberservation led him to give her one for the night as a way of introducing a friendship. Eleanor took the comic and returned it the next day, a routine that lasted for a couple of weeks before Park finally started a conversation. Following this discussion, Park began to share his music with Eleanor, which she would routinely return the following morning.
All the while, Eleanor was faced with difficult challenges in her home life; she and her father, Richie, continuously felt hatred towards each other, especially after Richie kicked Eleanor out for a year some time before the story begins; Richie was described as having a fair amount of anger, as shown by his constant abuse of Eleanor's mother. On account of the bathroom having no door, as Eleanor's house was seemingly not of the higher class, Eleanor had to come home after school immediately to take a shower so that Richie could not see her. Regardless of the tension she experienced in her household, Eleanor remained patient and did not show any sign of pain or despair in front of her classmates or Park.
Eleanor and Park's bond became tighter with the progression of time, and the two were extremely protective over one another; an encounter between Eleanor and a rude bully, Steve, ended Park kicking him in the face with great force and the emergence of a fight. Soon following the incident, Eleanor became Park's girlfriend, and their routine of spending time together grew into a daily visit of Eleanor to Park's house after school, where she would stay until dinnertime. Unfortunate circumstances regarding Eleanor's parents forbidding her to talk to boys at all forced Eleanor to tell her mother that she goes to a friend's house when going to Park's, choosing "Tina" as the name - the name of the rude girl that wouldn't let Eleanor sit on the bus.
The new couple encountered their first argument when Park saw what was written on Eleanor's books, which primarily consisted of foul language and phrases meant to make fun of Eleanor, a situation that instantly infuriated Park. Eleanor intended to hide the cruel display from Park, informing him that she was unaware of the culprits when he asked her who did it. Upon sharing her suspicions that Tina and her friends committed the act, Park defended Tina fiercely. Following the argument, Eleanor came to the realization Park and Tina were once romantically involved. Eleanor and Park did not speak to each other for several days until Eleanor visited him again and both parties apologized.
On another occasion, Eleanor's clothes were dumped into the toilet and flushed; she found them soaking wet while wearing her gym suit during gym class. Mrs. Dunne, the counselor, drove her home after Eleanor explained the situation. After many attempts, Park finally succeeded in getting Eleanor to share the story with him, for he saw her the other day and desired to know what happened to her.
Eleanor and Park's relationship moved in the positive direction for quite some time; their love continued to become more passionate, they got more time for themselves, and they finally experienced true happiness. This practical perfection lasted until suddenly Eleanor arrived at her house after a downtown adventure with Park to find all her siblings and mother crying with more severity than she had ever witnessed before. She read a threat letter in her box from Richie, realizing in that moment that he was the individual who wrote on her books. She crept out from her window and heard Tina calling her from behind the bushes, who then revealed to Eleanor that Richie was looking for her [Eleanor] everywhere with a great amount of anger, but Tina refused to tell him anything. Tina accompanied Eleanor as she fled to the comfort of Park, knowing the dangers of staying here and possible chances of death if found by her stepdad. Her only way to escape was to go to her uncle in Minnesota, and Park offered to drive her to his location instead of making her take the bus. Connections between Eleanor and Park slowly died away as both arrived safely, the conclusion of the tale of Eleanor and Park.