Connell is a bright student whose mother cleans Marianne' s house, Marianne the loner, the gifted and independent girl shunned by everyone at school. When they engage in an intimate relationship, Connell insists nobody must know anything about it.
Their first year at university will see them wander off and on dating other people, sleeping together again, breaking up after a misunderstanding but always keeping in touch as each feels a special connection to the other one.
Despite Marianne's weird desires and Connell's lack of communication skills, the couple eventually grow up, together or apart, and should one of them go away, the other one will be waiting.
Even though Sally Rooney's words and sentences may seem very simple and make for easy reading, her extremely specific descriptions of characters' gestures and inner thoughts make you feel you know these people, you have met them.
Of course you know them: they are normal people.