- Evan Peters as Kit Walker
- Sarah Paulson as Lana Winters
- Zachary Quinto as Dr. Oliver Thredson
- Jessica Lange as Sister Jude
- Lily Rabe as Sister Mary Eunice
- James Cromwell as Dr. Arthur Arden
- Joseph Fiennes as Monsignor Timothy Howard
- Lizzie Brocheré as Grace Bertrand
- Devon Graye & Lily Rabe as The Devil
- Chloë Sevigny as Shelley
- Naomi Grossman as Pepper
- Adam Levine as Leo Morrison
- Jenna Dewan-Tatum as Teresa Morrison
- Clea DuVall as Wendy
- Devon Graye as Jed Potter
- Chelsey Valentine as Missy Stone
- John Aylward as Father Malachi
- Robin Weigert as Cynthia Potter
- Andrew Rothenberg as Mr. Potter
As Halloween approaches, a troubled farm boy, who was believed to be possessed by a heinous devil, has been locked away in Briarcliff Asylum. The devil will soon reveal the darkest secret behind Sister Jude involved with the presumed deceased Missy Stone, and will bring ordeals to first Sister Mary Eunice and then everyone in the asylum.
The scene continued the scene of prievious episode when the a couple, Leo and Teresa, who travelled the ruins of Briarcliff Asylum, were attacked by a mysterious man dressed as the infamous killer, Bloody Face. Teresa tried to save Leo, but then winded up to the room where the killer mutilated Leo's arm. Through the door slot, Teresa watched in horror as Leo being mutilated by Bloody Face, and she pounded on the door.
While regretting to send her friend and lover, Lana, into Braircliff, Wendy was disturbed when the children who were trick-or-treating knock her door. Not long afterwards, Wendy sent the children away and made a plan to clear Lana's name, but before she could do so, Bloody Face had snuck into her house and killed her.
At Briarcliff, Sister Jude took Lana's secret notes about the asylum. Lana retorted that she could still remember what has happened to her, prompting Sister Jude to asked Dr. Arden to give Lana electroshock treatment. Asked to assist in administering the electroshock, Sister Jude was disturbed by the violence of the resulting treatment.
While under influences of eletric shock which her memories impaired, Lana continued to secretly document her experiences. Grace revealed to Lana that she knew of an escape route: the secret tunnel she first entered the asylum through. Grace agreed to assist her only if Kit be taken with them, which Lana refused, stating that she could never allow a serial murderer like Kit to go free.
Meanwhile, Kit, believed to be Bloody Face, had been interrogated by Dr. Oliver Thredson, who was a famous state psychiatrist and a new doctor to Briarcliff. Kit claimed he was completely sane and stated that his wife did not die. He said he saw her while being examined by aliens. Kit's words made Dr. Thredson worryingly belived that he was insane.
Meanwhile, under Dr. Arden's command, Sister Mary Eunice prepared raw meat in baskets and fed them to the savage creatures in the woods. She was curious about the creatures' identity. After his arrival, Dr. Arden presented Sister Mary Eunice a candy apple as his Halloween gift. Relucantly, Sister Mary Eunice cautiously took a bite. They looked at each other and smiled. As they were returning from woods, Shelly observed everything from her window and was jealous of Sister Mary Eunice's good fortune. Shelly then tried to seduce Dr. Arden, but was rebuked by him.
At his home, Dr. Arden hired a prostitute to dine with him, sternly demanding that she behaved docile and ladylike, which she relucantly did. He then demanded that she change into a nun's habit. While she is changing, she discovered a box. To her shock, the box was containing photographs of bound and mutilated women. Dr. Arden found her with the photos and menacingly blocked her way of escape from the room, but she managed to escape by attacking him and fled.
At Briarcliff, Dr. Thredson met Sister Jude and they had odds about treatments. Thredson was deeply disturbed about Jude's support to electroshock treatment and was shocked that Briarcliff patients lived a miserable life. As they were arguing, a couple entered Briarcliff and visited Sister Jude. However, as Dr. Thredson entered, they began to asked Thredson for help, much to Jude's dismay. Thredson then knew about the following situations.
The couple's son, Jed Potter, who was once a nice and kind boy, was developed a cruel and violent personality. One day, the boy killed the cow from his parents' farm and ate its organs, but then was unable to remember what he had done. They entered Jed's cell and found him deeply disturbed, but then Jed's eyes turned yellowish and roared to everyone in the room in Latin, making everyone believed he was possessed by a Devil.
Hearing the news, Monsignor Timothy Howard and Father Malachi arrived to perform an exorcism on Jed, and Dr. Thredson was shocked at the idea, informing him that he will report the sanitarium to the proper authorities. The Monsignor instead asked Dr. Thredson to join them, as an exorcism required the presence of a certified doctor, and Dr. Thredson agreed.
The exorcism began, and Sister Jude is dismissively told to leave the room, for "it is no place for a woman", much to her displeasure. Father Malachi was flung against a wall and Jed began screaming in Latin. The Devil who possessed Jed then revealed personal details about each of the participants' lives and flings objects around the room.
While the Monsignor escorted Father Malachi out, there was only Jude and Jed in the room. The Devil secretly taunted Sister Jude, revealing that she was previously a promiscuous, drunken bar singer by the name of Judy Martin who hit a young girl named Missy Stone while driving one night, and never reported the crime. Jude reacted in horror as illusions of Jed becoming Missy starting to taunt her. The Devil also undercovered more of Jude's dark past and her lust to the Monsignor. Jude was furious and angrily attacked the boy, but was saved from the situation by the Monsignor.
The chaos of the exorcism causes the power to fail and Lana and Grace make their escape. Grace refused to leave without Kit, and they both run to find their own way out. Lana screamd for the guards and made them caught Kit and Grace, sabotaging all of their chances at escaping.
As the blackout was over, Jed mysteriously died, but he stared at Sister Mary Eunice before he died, causing her to faint mysteriously. The next day, Dr. Arden visited Sister Mary Eunice and was surprised to found her on bed with her body exposed. After covering her legs with quilt, Sister Mary Eunice bid farewell to Dr. Arden, but after Dr. Arden left, she turned into an angry face and threw the quilt away. The cricifix on the wall started to shake strangely, hinting the nun was now possessed by the Devil.
Meanwhile, Jude called Lana to her office and praised her of sabotaging Grace and Kit's escape plan, and "rewarded" her to watch as they were caned. Lana was greatly disturbed by this.