In 1961 New Jersey, a single mother, Catherine Spages, raises her two daughters, Alice and Karen. The girls’ father, Dom, has remarried and lives in another town. The family is Catholic; they attend St. Michael’s Church, and are close to the young priest, Father Tom. One Sunday after mass, Catherine and her daughters visit Father Tom at the rectory. Karen is preparing for her first communion and Father Tom gives her a crucifix. Alice, jealous of the attention her younger sister is receiving, dons a mask and frightens Mrs. Tredoni, the priests’ housekeeper. At home, Alice plays alone in the basement of the Spages' apartment building. Wearing a St. Michael’s yellow raincoat and a mask, Alice plays with the doll she stole from Karen that was a gift from their father. Alice torments her sister and taunts their landlord, Mr. Alphonso, who rarely leaves his foul-smelling, cat-filled apartment. Later, during communion, Karen is strangled by someone wearing a mask and a yellow raincoat. Her body is dragged into the chapel next to the church, placed inside a bench, and lit on fire. The smoke draws the attention of a nun whose screams alert the congregation to the murder. As detectives investigate the killing, the girls’ father, Dom, arrives. Following the funeral, Catherine’s sister, Annie Deloreneze, and her family, including daughter Angela, attempt to comfort Catherine and Alice. Frustrated at the lack of progress in the case, Dom talks to Detectives Brennan and Spina and, later, learns from Father Tom that Alice has had behavior problems at St. Michael’s school and there have been repeated requests for a psychiatric evaluation. Father Tom explains to Dom that he thought he could handle the situation, but it had recently gotten worse. In the apartment building stairwell, Annie is attacked by the masked figure wielding a knife. When Mr. Alphonso and Catherine interrupt, the attacker flees. Dom and Father Tom arrive and a hysterical Annie is taken to the hospital. Dom looks through the basement and finds Alice with the stolen doll. She claims that Karen attacked Annie. At the hospital, Catherine tells Father Tom that Mr. Alphonso called the police and told them Alice attacked Annie. Spina arrives and interviews Annie, who also implicates Alice. However, Catherine says that Annie believes Alice is evil because she was conceived out-of-wedlock. Alice is taken into custody where she is given a lie detector test that she fails. Dom continues to investigate on his own, unable to believe that his daughter is the perpetrator, and he asks Father Tom for a list of people who purchased the yellow St. Michael’s raincoats, hypothesizing that Angela or another student could be the killer. Meanwhile, Alice is taken to a psychiatric hospital where Dr. Whitman diagnoses her as schizoid and violent with latent hostility toward her mother. Catherine and Dom reassure their daughter that they are doing what is best for her. Later, when Catherine is harassed by phone calls during which the caller breathes heavily and hangs up, Dom comforts her with a kiss, but the interlude is interrupted by a call from Dom’s current wife, Julia, who would like him to return home. Catherine urges Dom to leave, but Dom feels that he needs to stay until the killer is found. Dom continues to suspect Angela. At his hotel, Dom gets a call from someone claiming to be Angela who requests a meeting. When Dom goes to the appointed spot, he sees someone in a yellow raincoat and mask and chases the figure into an abandoned building, where he is lured upstairs. The figure stabs him in the shoulder, beats him with a brick, and ties him up. The attacker removes her mask and reveals herself to be Mrs. Tredoni. The priests’ housekeeper taunts Dom for being a “whore” before throwing him off the building to his death. The next day, Catherine goes to the rectory looking for Dom, but Mrs. Tredoni tries to send her away when Catherine insists on waiting for Father Tom. Mrs. Tredoni tells Catherine about losing her own daughter on the day of her first communion. Father Tom returns and tells Catherine about Dom’s “accident.” Meanwhile, Dom’s autopsy reveals a crucifix similar to the charm Karen received for her communion lodged in Dom’s throat. Father Tom takes Catherine to pick up Alice from the hospital, but Catherine decides to postpone telling Alice about her father. Meanwhile, Mrs. Tredoni dressed in white, looks through old photos, and places a knife, mask, and gloves in a paper bag. Acting on a hunch, Detective Spina, goes to the Spages' apartment building. Inside, Mr. Alphonso sleeps as a masked figure places an open jar of roaches on his stomach. The intruder is Alice. When Catherine and Alice leave for mass, Mr. Alphonso wakes up, startled by the roaches, and runs into the hallway where he meets another masked figure. Assuming the figure is Alice, Mr. Alphonso tears off the mask only to discover Mrs. Tredoni, who stabs him in the chest. When Detective Spina arrives, he hears screams, but is too late to save Mr. Alphonso. Later, at the church, Father Tom tells detectives that Mrs. Tredoni is inside and assures them that he can isolate her during communion. During the ceremony, Mrs. Tredoni, still carrying the bag with the knife, pushes forward to be next to Alice at the rail. When Father Tom refuses her communion and asks her to come with him, she stabs him in the neck, causing pandemonium in the church. As the police rush inside, Alice walks away from the altar carrying the bag with the knife.