Sabrina has a nightmare; wandering through the woods, she watches as her father Edward Spellman presents her as an infant to the Dark Lord. She then encounters three demons each holding a box in front of her. When Sabrina awakes, she magically tries on various clothes against the mirror while Salem watches. Her aunts Zelda and Hilda and cousin Ambrose Spellman comment about her choice of clothes and loud music. Sabrina tells her aunts about her plans to spend more of her time at the Academy of Unseen Arts, having obtained indefinite leave from Baxter High's new Principal Mary Wardwell. Zelda plans to take up a teaching position at the Academy.
At Baxter High, Lilith, still under the guise as Principal Wardwell, punishes Billy Marlin for chewing gum by forcing him to swallow it.
Harvey, Rosalind, and Susie talk about Sabrina's absence. Roz says that she needs time to sort things out. This year, Harvey's trying out for basketball. He and his father played together over the break. He'd been doing better since the magic eggnog Sabrina conjured up. Susie wishes to join Harvey on the boy's basketball team.
Father Faustus Blackwood introduces Zelda to the other faculty members. He assigns her to teach ancient tongues and sacred scripture. Father Blackwood has assigned his daughter Prudence to serve as Judas Blackwood's wet nurse and scolds her for letting the baby cry. Zelda calms Judas and chats with Prudence, asking if she has been giving him goat's milk.
Sabrina chats with Nicholas in the hall, who tells her about an academy tradition that Sabrina hopes doesn’t involve eating children. Father Blackwood informs the student body of an election for Top Boy, tasked with serving as a liaison between students and faculty. Sabrina, Nick, Ambrose, Luke, Prudence, Agatha, and Dorcas are in attendance. Nick is nominated. Sabrina offers to contest the election on the grounds that she had signed the Book of the Beast. She calls for all students regardless of their gender to have a voice. Nick nominates Sabrina and is seconded by Prudence. As part of the Top Boy selection, Father Blackwood announces that the candidates have to take part in three challenges at the Desecrated Church: the Inquisition, the Boil and Bubble, and the Conjuring. This will be followed by a vote.
Back at the Spellman home, Zelda and Hilda recall how Edward served as Top Boy. That appointment changed his life. A straight shot from Top Boy to High Priest. Ambrose tells Sabrina that he and Luke have been invited for a party to celebrate Nick’s nomination as Top Boy at Dorian's Gray Room, which is reserved for men. Zelda says Sabrina is too busy for her studies. Sabrina asks Ambrose and Luke if they will support her. Luke is unwilling, but Ambrose says he will wait to see how she will do in the three challenges first.
At the Academy, Cassius, the school's librarian, allows for Sabrina to read through books in the library to prepare for the test.
Meanwhile, Father Blackwood meets with the warlocks at Dorian Gray's Room and brings King Herod's daughter Salome to dance for their entertainment.
Back at the library, Sabrina's studying is interrupted by strange sounds. She encounters a demon called Asmodeus who claims he has brought tidings of filth and disease. He calls her a bastard witch and unleashes a plague of rats on her. Sabrina searches for a book of banishment.
At Dorian Gray's Room, Nick gets upset when Salome serves them an effigy of Sabrina’s bloody head, as a reminder from Father Blackwood of the only acceptable outcome from the trials.
As Asmodeus approaches Sabrina with a knife, she manages to banish him by reading a spell from a book of banishment.
Later, Sabrina tells Ambrose she was attacked by Asmodeus and his rats. She asked if Luke summoned the demon as they have to be summoned. Sabrina questions Ambrose about whether he will support her. Ambrose, in turn, questions her loyalty to the coven and her assault on tradition. Sabrina reiterates her goal to be Top Boy, as she believes she can make the coven better, generating a wind that causes the furniture to rumble. While Ambrose might not want to fight, Sabrina does. Hilda interrupts and sends Sabrina to bed.
Following morning, with the beginning of a new cycle, Prudence asks Father Blackwood if she can take up the Blackwood name and stand for Top Boy. However, he wouldn't allow for it. Sabrina and Zelda visit Father Blackwood to request a postponement due to the demonic attack, which is why Zelda has given her a witch-whistle and blinding powder. Father Blackwood refuses to grant Sabrina's wish, but gives her time to compose herself. In private, Prudence offers to help Sabrina get through the Inquisition.
At the Desecrated Church, Ambrose asks Luke about his whereabouts last night at the drinking party. Luke claims he had private business at the Academy with Father Blackwood. Zelda's in attendance in support of Sabrina. Father Blackwood begins the Inquisition and asks what is the Satanic symbol. Nick names the pentagram, gaining a point. He then asks Sabrina about the five books of the Lesser Key of Solomon. The Weird Sisters telepathically wire the answer to Sabrina. Father Blackwood asks her the date of birth of the Magus John Dee. The Weird Sisters tell Sabrina that the answer is July, 13 1527. He then asks about the year of death, which Sabrina names as 1608. He then quizzes her on the publication date of the Malleus Maleficarum, the date of the Salem Witch Trial, the Pendle Trials, the birth and death of Anne Boleyn, and the death of Rasputin, which she answers correctly.
At Baxter High, during the try-outs, Susie encounters hostility from some of the boys, particularly Billy and Carl, who reject her because of her non-binary gender and insist that it is a boys' team. Harvey comes to her defense, however, Coach Craven doesn’t want to allow a girl on his team. And so Rosalind reminds Susie that when others go low, they go high.
Hilda meets with Principal Wardwell and asks about the changes in Sabrina. Wardwell attributes the changes to the dark baptism. Hilda thinks that Sabrina’s changes are a prelude to darker changes. Hilda asks Wardwell to suggests that Sabrina come back part-time to spend more time with her mortal friends. Wardwell says there is nothing she can do since Sabrina has chosen to study full time at the Academy. Susie, Harvey, and Rosalind request a meeting with Principal Wardwell to inform her of Coach Craven's refusal to allow Susie to try-out. Wardwell confronts Coach Craven about his refusal to let Susie try out for the basketball team. Craven agrees to allow Susie to try out despite her lack of skills.
Father Blackwood accuses Sabrina of cheating, which is punishable by lashing. Sabrina says she wants to change the traditions at the Church of Night but Father Blackwood insists that the position of High Priest has always been held by a warlock. He vows there will never be a High Priestess. Sabrina refuses to back down. Father Blackwood warns he will seal the Desecrated Church to ensure that no external forces can interfere with the Boil and Bubble challenge. Sabrina vows to study for the test.
While walking through the woods on her way home, Sabrina is attacked by a second demon named Purson, who unleashes a flock of bats on her. Sabrina hides under a stone table and manages to drive away the demon by blowing her witch-whistle. Sabrina makes it home, where she tells aunt Hilda that someone is sending demons to attack her. She asks about the Boil and Bubble challenge, which fortunately for Sabrina, Hilda is the Academy's all-time reigning champion bubbler. After Sabrina has changed, Hilda tells her that the test involves memorizing spell potions. Hilda questions if all this trouble be Top Boy is worth it. Sabrina doesn't think her old friends would welcome her even if she wanted to come back. Hilda reassures Sabrina that signing the Book of the Beast doesn't changes who she is. Sabrina is worried about signing her soul away. Hilda says she also did but Sabrina warns that the Dark Lord summoned her to do his bidding. She says she doesn't want to be near her mortal friends when he does.
At the Boil and Bubble challenge, Sister Shirley confronts Zelda about her relationship with Father Blackwood, which Shirley remarks as being shameful considering his wife just died. Some are even saying Zelda had a hand in her demise. During the Boil and Bubble, Father Blackwood briefs Nick and Sabrina that they have to make potions. Each adding a component. Whoever adds the wrong ingredient with the wrong phraseology loses and must drink the spoiled concoction. Sabrina goes first and places the molted skin of a cobra snake into a cauldron. She passes the first test. Nicholas cools the potion with a newborn's blood, passing his test. Sabrina places the blind white eye of a cave-born shark into a brew, causing it to bubble. The brew putrefies and Sabrina is obliged to drink it. Nick tries to stop her from drinking it but she drinks it and vomits it out. Several people cheer for here.
Hilda gives Sabrina some Pepto and encourages her to visit her mortal friends. Hilda tells Sabrina that Susie is trying out for the basketball team today along with Harvey. Sabrina sympathizes with Susie wanting to join a traditionally male team. Sabrina takes her aunt's advice and visits Baxter High, where Harvey and Susie try out for the basketball team, and Rosalind cheer them on from the sideline. Susie performs terribly, and Billy and Carl even knock her over. So, Sabrina uses her magic to help Susie shoot the ball through the hoop. Principal Wardwell notices Sabrina's incantations. Susie is overjoyed and Harvey and Rosalind hug her. Susie then reveals to them that she, or rather now he, identifies by his male identity "Theo." Sabrina experiences flashbacks of signing the Book of the Beast and leaves.
In Baxter High's corridors, Sabrina is kidnapped by a third demon who takes her into the boiler room by a demon named Beelzebub. Before the demon can harm her, he is stopped by Principal Wardwell, who binds the demon. Beelzebub stood beside the Son of Dawn, before witch and mankind walked the earth, but he doesn't initially recognize Wardwell. As he comes to realize that she is in fact Lilith, she banishes him. Afterward, Mary suggests that Sabrina transfer back to Baxter High considering the constant threat she faces. Sabrina tells Wardwell about her campaign to be Father Blackwood's Top Boy, challenging the patriarchal tradition. Sabrina tells Wardwell that Nick Scratch is a friend. Wardwell tries to sow a wedge between Sabrina and Nick, suggesting that he may be trying to sabotage her.
Zelda tells Father Blackwood that some members of the coven oppose their relationship. She asks Blackwood to clarify their relationship. He tells her she is one of his disciples and his son’s Night Mother, as well as his night maiden. Zelda asks if he wants to make her his Top Lady. Blackwood says there is a mourning period they must respect given Constance's recent passing. Zelda says she will tone down their relationship until he is ready to legitimize their relationship.
Sabrina visits Nick, who is preparing for the conjuring contest. She asks Nick if he sent the demons after her. Nick denies sending the demons with the rats, bats, and flies. He realizes that the demons are Three Plague Kings whom he does not have the power to summon. Sabrina thinks it is Father Blackwood, and Nick agrees to help her find out.
During the Conjuring test, which Zelda and the Weird Sisters attend, Sabrina and Nick strike a deal to expose Father Blackwood. So, they draw circles on the ground and seal them together in hopes of summoning the Plague Kings and getting answers. Sabrina accuses Father Blackwood or a member of the coven of sending high demons to attack her. Nick backs Sabrina up and tells Blackwood that they want to know the truth and summon the Plague Kings. The Plague Kings identify themselves as Beelzebub, Asmodeus, and Purson. Sabrina demands to know who sent them to kill her. The Plague Kings claim they operate independently of Satan and the coven but that they wish death on the "half-breed" Sabrina because of the chaos she will bring. "The half-witch must not ascend," Nick questions the demons, but Father Blackwood banishes the three of them.
Father Blackwood summons Nick and Sabrina into his office. Nick says that the demons acted on their own volition, meaning something must have them riled up. Father Blackwood decides that neither of them is worthy of the title of Top Boy and instead designates Ambrose as Top Boy. He makes Ambrose a full-time student. Father Blackwood proceeds to talk with Ambrose in private.
Nick compliments Sabrina for her fighting spirit. He then asks her to take him to Cerberus Books to celebrate. Meanwhile, Rosalind and Harvey discuss Theo's decision to identify as a boy. Roz says that he was born as a boy and is ready to embrace his identity. Harvey asks if Sabrina knew about Theo. Harvey admits to missing Sabrina. Roz has a vision of her kissing Harvey in the school corridor.
Sabrina confides with Nick that she had help from the Weird Sisters in the first challenge, which he had already figured. They spot Harvey and Roz in Dr. Cerberus together and instead, decide to go to Dorian Gray's Room despite it being a warlock's club. Dorian agrees to serve both Sabrina and Nick because they are beautiful, despite the fact that they don't usually serve witches. Sabrina asks Nick about what the demon meant when he said that the "half-witch must not ascend." She thinks that the demons don't want her to be High Priestess. Nick is supportive of Sabrina’s dream to become High Priestess.
From Mary Wardwell's home, Lilith summons the Dark Lord. She confronts him about withholding information about Sabrina's importance to his plans.
- Epiphany is a Christian feast day that celebrates the revelation of God incarnate as Jesus Christ.
- Sabrina changing in front of the mirror is a reference to the opening credits of the first three seasons of the sitcom Sabrina the Teenage Witch.
- The faculty members who Faustus Blackwood introduce Zelda to are named after famous American writers of the turn on 20th century, known for their supernatural and cosmic horror works: Arthur Machen, H.P. Lovecraft, Ambrose Bierce, and Shirley Jackson. The themes of these authors are constantly referenced through the series. Sister Carswell is a reference to Carswell Prison, whose medical facility has a reputation for being haunted.
- Susie comes out as trans and introduces himself to Roz and Harvey as "Theo".