In a school in small-town west of Ireland, Connell is a well-liked, good looking and athletic student. Marianne is a proud, intimidating and unpopular loner who actively avoids her classmates and questions her teachers’ authority.
Connell and Marianne’s relationship continues in secret and they sleep together for the first time. At school, Connell makes excuses for why he didn’t see his friends at the weekend and evades questions on his mother’s job at Marianne’s house. A girl in his friendship group, Rachel, gets impatient with Connell’s lack of interest and tensions build for Connell.
The night of the Debs is approaching and the girls at school have organised a fundraising event. Marianne has been asked to help and is out of her comfort zone. At the club, one of Connell’s friends Karen does her best to show Marianne some kindness but Rachel behaves coldly towards her.
Months later, school has finished and Connell arrives at Trinity College, Dublin. He has found a room in a house-share and meets his new housemate Niall. Despite his efforts, he feels out of place and struggles to articulate himself when surrounded by his eloquent and wealthy peers.
Connell and Marianne start socializing as friends in Dublin. She introduces Connell to her group and one of her friends, Teresa is interested in him. Marianne is still dating Gareth. but her interest in the relationship is starting to fade. Marianne eventually finishes things with Gareth and makes a drunken pass at Connell.
Connell and Marianne are back together. Connell has gained confidence in college; giving presentations in class and getting good grades but is reluctant to show Marianne affection in front of her friends. Will the two be able to admit that they are together?
Connell bumps into Marianne back in Sligo. It’s the first time they have seen each other since they broke up. Connell asks Marianne how she is and tells her he has heard that she’s now seeing Jamie. Despite the awkwardness between them, Connell offers to attend Marianne’s father’s anniversary mass the next day and they agree to stay friends.
It’s the summer holidays and Connell and Niall arrive at Marianne’s family house in Italy. The obvious chemistry between Connell and Marianne causes friction with Jamie, despite Connell’s evident happiness with his girlfriend Helen, who he clearly misses.
Marianne is on a student exchange program in Sweden for a year. Her breakup with Jamie has cost her some of her friends, but she is still in touch with Connell and Joanna. She is in a relationship with Lukas, a photographer who she meets at a college party.
Connell and Helen are out celebrating New Year’s Eve in Dublin. Late that night, Connell receives a group text questioning the whereabouts of Rob. The next morning news comes through that Rob has died. Connell struggles with the emotional fallout of Rob’s death.
Marianne has returned to Carricklea for the summer. She and Connell spend their weekends together, even though he is still living in Dublin. After a night out together, they start to discuss their friendship and inevitably their attraction.
Marianne and Connell are back in Dublin and together as a couple. Life is calm and they are at ease with each other. Then Connell receives news that he has been offered a place to study in New York. Neither of them know how to process the news and so they decide to let it sit.