Trifles tells the story of two investigations into the murder of John Wright. The male characters carry on the official investigation while the female characters carry on their own unofficial investigation.
The play opens when its five characters enter the kitchen of the Wright farmhouse. The county attorney takes charge of the investigation, guiding the sheriff and Mr. Hale in recounting their roles in the discovery of the crime. Mr. Hale tells how he came to the house to ask John Wright about sharing the cost of a phone line, only to find Mrs. Wright sitting in a rocker. When he asks to speak with her husband, Mrs. Wright says that he cannot speak with Mr. Hale because he is dead. Mr. Hale investigates and finds that Wright has been hanged. After commenting on Mrs. Wright’s poor housekeeping in ways that irritate the women present, the county attorney leads the men upstairs so he can search the scene of the crime for a motive.
The women are left alone. While gathering some household goods to make Mrs. Wright feel more at ease in jail, they discuss Minnie Wright, her childhood as Minnie Foster, her life with John Wright, and the quilt that she was making when she was taken to jail. The men reenter briefly, then leave. The women discuss the state of the Wright household before Mr. Wright’s death. In the process, they communicate how greatly Mrs. Wright had changed over the years and how depressing her life with John Wright had been. The women express sympathy over what the kitchen disarray would mean emotionally to Mrs. Wright and how much of an intrusion it was for her to have all of these outsiders searching through her goods. The women discover Mrs. Wright’s pet bird. It has been killed, and Mrs. Wright had hidden it in her sewing box. The women’s eyes meet, but they do not speak directly about the bird. When she hears the men returning again, Mrs. Hale hides the dead bird.
Once the men have left again, the women discuss past pains and losses that parallel those that Mrs. Wright has suffered. A boy killed Mrs. Peters’s kitten when she was a child, and she was childless for a time, like Mrs. Wright. The women express a shared sense of responsibility for her isolation and suggest that they were criminally negligent to allow her to be entirely alone. Just before the men reenter, Mrs. Peters suggests that they are getting too upset over a dead bird.
The county attorney summarizes the case as he enters and indicates that the entire case is clear except for a missing motive. As the investigation ends, the sheriff asks the attorney if he needs to inspect the things the women are taking to Mrs. Wright in jail. The county attorney dismisses this jokingly, suggesting that there is no need because the sheriff’s wife, Mrs. Peters, is essentially married to the law. When the men leave the room to check one last detail, the women’s eyes meet again. Mrs. Peters tries to hide the box containing the dead bird in the bag of quilt pieces she is taking to Mrs. Wright, but it does not fit. Mrs. Hale hides the box in her coat pocket. When the men reenter, the women have one last chance to share this clue with them. They do not, and the play closes.