The Reverend Parris, watching over his sick daughter Betty, is wondering what is wrong with her. It is soon revealed that the entire town is talking about rumors that Betty is sick because of witchcraft. Rev. Parris had seen both Betty and his niece Abigail dancing in the forest with his slave, Tituba, the night before. That evening in the forest, he also saw Tituba waving her arms over a fire, a dress on the ground, and someone naked running around their circle. When first questioned, Abigail denies that she or Betty have been involved in witchcraft, but she admits that they were dancing in the forest with Tituba. Abigail lives in the Parris household. She used to live and work at the home of John and Elizabeth Proctor, but was dismissed due to her illicit relationship with John Proctor.
When another couple, Thomas and Ann Putnam, arrives at the Parris household, they admit they had consulted Tituba, in the hope she could conjure up the spirits of their seven dead offspring. They wanted to find out why all seven babies died so soon after childbirth. To Reverend Parris's horror, the Putnams emphatically state that his slave Tituba consorts with the dead. The Putnams's only living child, Ruth, is now struck by a similar ailment as Betty Parris. When the minister and the Putnams are out of the room, Abigail threatens to harm the three other young girls in the room if they speak a word about what they did in the forest with Tituba.
John Proctor comes to see what is wrong with Betty. He confronts Abigail, who says that Betty is just pretending to be ill or possessed by evil spirits. As Proctor and Abigail have this conversation, it becomes clear that the two of them had had an affair while she worked in the Proctor household and Proctor’s wife, Elizabeth, was ill. Abigail tries to flirt with Proctor, but he tells her the relationship is over. Proctor during this conversation does show slight signs of the feelings he once felt for Abigail but does well to hide them, as he regrets the affair. Abigail blames Elizabeth for John's behavior, and tells him they will be together again someday.
When Betty starts to fit, Parris and the Putnams return with Rebecca Nurse. She has had many children and grandchildren and knows that Betty and Ruth are pretending. She says they will stop when they tire of it. Soon, the Reverend Hale arrives at the Parris home. Hale is a famed witch expert from a nearby town. Suddenly, in front of Hale, Abigail changes her story and begins to suggest that Tituba did indeed call on the Devil. Tituba, surprised at this accusation, vehemently denies it. But when Hale and Parris interrogate Tituba, under pressure she confesses to witchcraft, and fingers several other women as “witches” in the village, including Sarah Good and Sarah Osborne. While Tituba and Abigail are accusing women in the town, several other young girls, including Mary Warren (who now works in John Proctor's household) follow Abigail’s lead and begin accusing other women as well.
This act gives an introductory insight into Abigail's leadership, as she frightens the other girls into following her lead. The girls now have power and in Salem, a place where women, especially young girls, have little influence, they take this opportunity of power by the end of Act One by naming people in the town to be accused of witchcraft. These names have been mentioned, not by the girls or Tituba, but by Parris and others. The names the girls and Tituba mention are regurgitations of names given by the men.