A council chamber. Two dead bodies of young men are covered and taken away. People exit the room, leaving a grieving mother. The narrator explains the story. We find the woman is Mrs. Johnstone (Overture).
The story begins: Mrs. Johnstone explains how she has come to be a single parent of 7 and expecting (Marilyn Monroe).
Mrs. Johnstone has found a job cleaning house for Mrs. Lyons, an upper class woman. She learns she is expecting twins, and realizes some of the children might have to be taken from her by the welfare. Mrs. Lyons, unable to have children, expresses her need for a baby, and has an idea (My Child), which she cons Mrs. Johnstone into thinking is a good one. She promises that Mrs. Johnstone will be able to see her baby anytime. Her husband (Mr. Lyons, who has been away for nine months) will believe the baby is truly hers.
Mrs. Johnstone gives birth to two boys, Michael and Edward. She comes home from the hospital to find men taking away ordered items she couldn't pay for, and sings of how everything slips away from her, even one of her sons which she is about to give away (Easy Terms).
Meanwhile, Mrs. Lyons comes to take her baby, Edward.
Mrs. Johnstone is at work, playing with Edward on her break. Mr. Lyons is told a lie by his wife: Mrs. Johnstone's work is deteriorating and she must be fired. Mrs. Lyons fires Mrs. Johnstone, and tells her that she will never see Edward again because if the twins are ever told what they are, they will die, according to superstition. Mrs. Johnstone, highly superstitious, leaves, afraid and upset (Shoes Upon the Table).
The plot has advanced seven years. Mickey Johnstone meets an upper class boy, his age, who introduces himself as Eddie Lyons. The two "decide" to be best friends, and discover that they share the same birthday. Not knowing anything, they assume it's a coincidence and believe they were meant to be brought together. They ***** their fingers and mix the blood. The are now Blood Brothers (July the 18th).
Mickey is playing games with his friends, his older delinquent brother, Sammy (Kid's Game), and his best friend Linda.
Both of the mothers are now aware of the boys' budding friendship, and inform their children they cannot play together. Disobeying, Eddie leaves to play with Mickey and Linda, leaving Mrs. Lyons in a worried state (Gypsies in the Wood).
Cold-hearted Mrs. Lyons, who has her husband wrapped around her finger, decides they must move away to the country to escape the Johnstones. Her husband agrees, and they inform Edward, who is sad he must leave Mickey.
Mickey says his good-byes to Eddie and leaves. Mrs. Johnstone says a private good-bye, unable to bear that her other son will be gone. She gives him a locket with a picture of herself and Mickey in it for memories.
Mickey, alone, sings of his loneliness (Long Sunday…