In the first scene, Helen and her teenage daughter; Jo, are moving into a shabby flat. Within a few minutes we learn that they have little money, living off Helen's immoral earnings (the money given her by her lovers, although she is not a true prostitute, being more of a "good time girl"). Helen is a regular drinker, and she and Jo have a rather confrontational and ambiguously inter-dependent relationship. As they settle in, Helen's surprise at some of Jo's drawings both suggests Jo's talent and originality and shows Helen's lack of interest in and knowledge about her daughter. Jo rejects the idea of going to an art school, blaming Helen for having interrupted her training all too often by moving her constantly from one school to another. Jo now only wants to leave school and earn her own money so that she can get away from Helen. After this exposition of their past lives and present relationship, Peter (Helen's younger boyfriend) comes in. Jo assumes that Helen has moved here to escape from him, but we are never told the reason why. Peter had not realised how old Helen was until he sees her daughter. Nonetheless he asks Helen to marry him, first half jokingly, then more or less in earnest. When Peter leaves, most of the basic information about the two women characters has been given, and most of this has arisen quite naturally through the dialogue.
The second scene consists of four main parts, Jo's meetings with her boyfriend alternating with her confrontations with Helen. Thus we are made to see how Helen's indifference makes Jo look for happiness in other places. It begins outside: Jo is walking home in the company of her black boyfriend. During a light-hearted, semi-serious dialogue, he asks her to marry him, and she agrees, although he is in the navy and will be away on his ship for six months before they can marry. The boyfriend gives Jo a ring which she hangs round her neck under her clothes in order to hide it from Helen. From the conversation we learn that Jo is really leaving school and is going to start a part-time job in a pub. The next sequence takes place inside the flat (without a change of scenery). Helen informs Jo that she is going to marry Peter. Peter enters, and a dialogue that is frequently hostile but also funny evolves among the three: instead of only Jo and Helen attacking each other, a more complex pattern evolves, with Jo attacking the others, the others attacking Jo, and Helen attacking both Peter and Jo. Jo is truly upset at the thought of Helen marrying Peter, but also pesters and provokes him in an effort to antagonise him even more. After Helen and Peter leave her on her own for Christmas, Jo weeps and is consoled by her boyfriend. She invites him to stay over Christmas, although she has a feeling that she will never see the boy again. After a pause and some moments of darkness on stage, we see Helen and Jo on stage, on the occasion of Helen's wedding day after Christmas. Jo has a cold and will not be able to attend at the wedding. Since she is in her pyjamas, Helen catches a glimpse of the ring around her neck and learns the truth. She scolds Jo violently for thinking of marrying so young, with one of her occasional bursts of real feeling and concern for her daughter. Asked by Jo about her real father, Helen explains that she had been married to a "Puritan" and that she had to look elsewhere for sexual pleasure. Thus she had her first sexual experience with Jo's father, a "not very bright man," a "bit retarded". She then hurries off to her wedding.
Several months later, Jo is living alone in the same old shabby flat. She works in a shoe shop by day and in a bar in the evenings in order to afford the rent. She is pregnant, and her boyfriend has not (yet?) come back to her. She returns from a funfair to the flat in the company of Geoff an "effeminate" art student, who has possibly been thrown out from his former lodgings because his landlady suspected he was gay. Jo offends him with her insensitive inquisitiveness about his sexuality, and he in turn maliciously criticises her drawings. She apologises and asks him to stay, sleeping on the couch. Geoff shows concern for Jo's problems, and they develop a friendly, joking relationship. A moment of darkness marks the passage of time, and next we see Jo irritable and depressed by her pregnancy, with Geoff patiently consoling her. Then, seeking reassurance himself he kisses her and asks her to marry him. Jo says that although she likes him she cannot marry him, and he misses that she makes a sexual pass at him, something confirming that "it is not marrying love between us". At this point, Helen enters. She has been contacted by Geoff, who wishes to keep this fact secret from Jo. Jo, however, guesses that much and is angry with both Helen and Geoff. Whenever Geoff tries to interfere in the quarrel between the two women, he is attacked by one or the other or both. As Helen is offering Jo money, Peter comes in, very drunk, and takes back the money and Helen's offer of a home to Jo. He leaves insisting that Helen come with him; after a moment's hesitation she runs after him.
In the second scene of act two, the baby is due any moment. Jo and Geoff seem happy. He reassures her that Helen was probably mistaken about or exaggerating the mental deficiencies of Jo's father. Geoff has bought a doll for Jo to practise handling the baby but Jo flings it to the ground because it is the wrong colour: Jo assumes that her baby will be as black as its father. Her momentary outburst against the baby, motherhood and womanhood is short-lived, however, and she and Geoff are about to have tea when Helen enters with all her luggage from Act 1. Apparently, she has been thrown out by Peter and now plans to stay with Jo. In order to get rid of Geoff, she behaves very rudely to him, while overwhelming her daughter with advice and presents. Jo defends Geoff, but while she is asleep, Geoff decides to leave since Helen is too strong for him and he does not want to tear Jo to pieces. When Jo wakes up, Helen pretends that Geoff is out doing the shopping. When she learns that the baby will be black, she loses her nerves and rushes out for a drink, despite the fact that Jo's labour pains have just begun. Alone, Jo happily hums a tune Geoff sang before, still not having realised that he is gone.