Salford. Jo is a teenager about to finish school. She is illegitimate and lives with her feckless mother, Ellen. Behind on the rent, they run away from their landlady and cross over town to new, bleak lodgings in a slum area. A young black man, Jimmy, helps Jo off the bus with her cases.

Ellen brings back her new, younger lover, Peter, to the lodgings but is embarrassed by Jo and makes him leave. Discovering Jo's art portfolio, Ellen realises she has talent, but fails to dissuade her from leaving school.

After detention for clowning around in class, Jo falls down the steps and hurts her knee. Walking along the canal she meets Jimmy, who is a cook on a ship. He treats her injury and they kiss. Meanwhile at a dance hall, Peter asks Ellen to live with him. When Jo comes home, Ellen tells her she will be getting married and that she and Peter will be going to Blackpool. Jo insists on coming to Blackpool, much to Peter's irritation. In Blackpool they visit all the attractions but Jo is cheeky and troublesome throughout, enraging Peter. Ellen agrees to send her home.

Jo arrives home to find Jimmy waiting for her. He tells her that his ship sails tomorrow. Jo asks him to make love. In the morning she watches him board the ship.

When Ellen returns home she starts getting ready to move in with Peter. Jo asks about her father. Ellen tells Jo he was a bit simple and that it was her first time and only happened once.

Jo starts a job in a shoe shop and rents a large, derelict flat in the slum district. She befriends a young homosexual, Geoff, who resists her demands to tell her details about his sexuality but agrees to move in with her, undertaking most of the domestic chores.

Jo tells Geoff that she is pregnant. She is unhappy about it but doesn't want to have an abortion. They go for a day out in the country and Geoff tries to kiss Jo, offering to be her husband for the baby's sake. Jo rejects his suggestions.

Geoff makes Jo read up on baby care. Despite Jo mocking his lack of confidence, he tells her that that he didn't much care whether he lived or died before he met her. He goes to the antenatal clinic and is given a doll for Jo to practice with. Jo is becoming scared and upset by impending motherhood and the way her life is and throws the doll on the floor.

Geoff visits Ellen to ask her to help Jo. She treats him coldly but comes to visit with a drunken Peter in tow. They all, row but Ellen's position in Jo's life is partially re-established. After Ellen goes Geoff makes clear his platonic devotion to Jo and wish to help look after the baby.

Ellen reappears at the flat and she and Geoff argue over Jo, who is now very heavily pregnant. Jo tells Ellen that she wants Geoff to stay but she does not pass the message on. It emerges that Peter has thrown Ellen out to go off with a younger woman. Jo tells her that the baby's father was black. Ellen has now taken Geoff's place, and he leaves quietly with a note for Jo wishing her luck. For a while, he stands in the yard watching the local children put a guy on a lighted bonfire. He sees Jo appear on the other side of the fire but she doesn't see him and he leaves. One of the children gives Jo a sparkler to hold.