The first act introduces the audience to most of the major characters, as well as a surface-level plot complication. It begins with Betty, daughter of the town's embattled Reverend Parris, lying in bed in a seemingly catatonic state. The Puritan town is abuzz with rumors of witchcraft, and many people are speculating that Betty is bewitched. John Proctor, the play's tragic hero, enters and tells Abigail that the situation is only "mischief." Reverend John Hale, an expert in the dark arts, enters and begins to diagnose Betty's condition. The characters discover that a group of teenage girls had been conjuring spirits in the woods the night before with Reverend Parris's Barbados slave, Tituba. The act ends with Betty, Abigail, and Tituba confessing to seeing various townspeople with the devil.
Act II takes place at John Proctor's home, and at its beginning the audience is introduced to Proctor's wife, Elizabeth. Elizabeth and John Proctor have a strained relationship, and the audience infers that Proctor has been unfaithful to Elizabeth. Elizabeth's dialogue indicates that John knows the girls' accusations are fraudulent, and that Abigail is at the center of the accusations. The Proctor's servant breaks the news that Elizabeth has now been accused of witchcraft, and the act ends with the town's marshal arresting Elizabeth as Proctor cries out her innocence.
The setting of Act III is the Salem courthouse, where many of the town's prominent people are being tried on charges of witchcraft. The judges are convicting townspeople based on spectral evidence, and it appears that false accusations are rampant as neighbors accuse one another for personal gain. Proctor admits an affair with Abigail, finally discrediting her and the other girls, but when Elizabeth is called in to confirm his confession she does not admit his adultery because she would not soil his good name. The act ends with Proctor's declaration that "God is dead," and he is led away to jail.
In the Salem jail, several months later, day is breaking, and John Proctor is to be executed with the sunrise. Townspeople have revolted against the corrupt judicial system, and Reverend Parris and the judges involved are looking for any evidence that the previous executions were just. Proctor is given an opportunity to confess to witchcraft and, thus, spare his life, but he chooses instead to make peace with his wife for his past sins and die on the gallows an honorable man. At the end of the play, Proctor is led away to his execution (Reference 2).
The Crucible paints a grim picture of mass hysteria and its effect on a society. While Miller chose to set the play in Puritan times, many parallels can be drawn to other periods in history, including the McCarthy trials of the 1950s, the Japanese internment camps during WWII, and even the AIDS outbreak of the early 1980s.