The night of the Debs is approaching and the girls at school have organised a fundraising event. Marianne (Daisy Edgar-Jones) has been asked to help and is out of her comfort zone. At the club, one of Connell's friends Karen (Niamh Lynch) does her best to show Marianne some kindness but Rachel (Leah McNamara) behaves coldly towards her. The evening turns sour, when one of the boys' older friends gropes Marianne. She leaves the club, upset by the incident and Connell (Paul Mescal) offers her a lift home. Marianne stays over at Connell's house and bumps into Lorraine as she leaves the next day. Connell becomes anxious when his friends tease him about Marianne, suspecting they've guessed about their relationship. Fuelled by anxiety, Connell makes an unexpected decision that hurts Marianne and causes a rift between him and his mother, Lorraine (Sarah Greene). Marianne withdraws from school, causing Connell intense guilt.

Months later, school has finished and Connell (Paul Mescal) arrives at Trinity College, Dublin. He has found a room in a house-share and meets his new housemate Niall (Desmond Eastwood). Despite his efforts, he feels out of place and struggles to articulate himself when surrounded by his eloquent and wealthy peers. Connell reluctantly accepts a party invite from new classmate Gareth (Sebastian De Souza). Feeling intimidated by the fashionable crowd in attendance, Gareth offers to introduce him to someone else he knows from Sligo and so he comes face-to-face with an unexpected guest.

Connell (Paul Mescal) and Marianne (Daisy Edgar-Jones) start socialising as friends in Dublin. She introduces Connell to her group and one of her friends, Teresa (Lauryn Canny) is interested in him. Marianne is still dating Gareth (Sebastian De Souza), but her interest in the relationship is starting to fade. Marianne eventually finishes things with Gareth and makes a drunken pass at Connell.