On Halloween 1985, the hospital staff of Our Lady of Perpetual Suffering, which was originally built as a tuberculosis clinic next to a swamp, parties instead of looking after their patients. A heavily pregnant woman demands that the nurse find a doctor to help her husband, Bill. The nurse finds Dr. Mike, who is dressed in a green devil costume, who agrees to perform emergency surgery. Instead, Dr. Mike and the nurse dump the sedated man in the swamp and throw Dr. Mike's Halloween costume over him, intending to fake the paperwork saying that the man checked himself out after the surgery, so that they can go back and party.
In present day 2016, Dr. Brock Holt and Dr. Cassidy Cascade see their first patient, Catherine Hobart, who suffers from Werewolf Syndrome at CURE, the teaching hospital opened by Cathy Munsch. Munsch claims that she opened the hospital to fix the broken healthcare system.
Munsch recalls the Chanels getting their murder convictions overturned on appeal after a Netflix documentary series brought them fame and Denise Hemphill presented video evidence of Hester Ulrich confessing to the crime (because she thought once someone was convicted she could not be convicted of the same crime).
Munsch finds Zayday at her menial waitressing job, where Zayday has been working (along with two other jobs) to put herself through medical school. Munsch offers to pay for her schooling via giving her a residency at the teaching hospital. Zayday is initially suspicious of Munsch's motives but agrees.
Zayday meets Dr. Holt and Dr. Cascade. Holt tells the two the story of losing his hand in a freak Superbowl Party accident and getting a hand transplant. He feels he owes Munsch for giving him a second chance. Zayday notices that Cascade feels unnaturally cold.
Cascade and Holt believe that Catherine Hobart is hopeless, but Zayday is insistent that they just need to try harder. Chamberlain Jackson, the unpaid, super upbeat candy striper, bursts into Catherine's room in an attempt to cheer her up but ends up making her more upset.
Zayday convinces Munsch to hire more women at the hospital, since it is currently just Zayday and a bunch of male doctors.
The Chanels, after having been released, are social pariahs. They go back to college to finish their degrees (majoring in Communications) and get menial jobs but are still totally broke and miserable.
Cathy Munsch finds them where they're living and tells them to enroll as medical students and come to work at her teaching hospital. #5 is happy to agree right away but Chanel is more hesitant. Munsch convinces them and they go to the hospital. Zayday is initially shocked to see them but eventually embraces them and says this will be so much fun.
Zayday and Munsch take the Chanels to the locker room, where they're given scrubs. Chanel at first refuses to wear the scrubs but then sees Dr. Holt in the locker room shower and immediately takes off her clothes. #5 spots a prominent tattoo that Holt has. Munsch instructs the Chanels to "ghost" shadow the doctors as they see patients. The Chanels agree.
Zayday presents her research to Catherine Hobart, telling her of an experimental treatment in which they'd drill a hole in her head. The Chanels gawk at Catherine and act very inappropriately, asking invasive and rude questions. Catherine is hesitant to get a lobotomy, and Zayday gives her a consent form to look over and sign if she decides that she wants to move forward with it.
The Chanels have a run in with the nurse and administrator of the hospital. After she overhears Chanel say that, as doctors, the nurses are their underlings, the head nurse Hoffel threatens Chanel and tells her that she doesn't like her.
Zayday has the Chanels called to Munsch's office, where Munsch confronts them over their inappropriate behavior in the patient's room. She puts them on academic probation, assigns them essays, and informs them that, despite their mistaken beliefs, they're not getting paid doctor salaries on top of the free room and board and medical school. The Chanels are horrified.
Back in their room, the Chanels debrief at the end of the day. Chanel decides that they can aim to be TV doctors and hopefully get their own show. Chanel decides they must outwit Zayday in order to stand out as better doctors than her. Chanel ditches #3 and #5 to go flirt with Dr. Brock.
Together, the two of them manage to come with a solution -- Catherine is ingesting too much testosterone, so Brock prescribes her a soy diet and hair growth blockers. Chanel rubs it in Zayday's face that they were right and her idea to perform the lobotomy was wrong. Later, Catherine loses ALL of her hair, but the Chanels give her a makeover, complete with a wig.
Nurse Hoffel still hates the Chanels and Munsch tells her to keep on riding them hard, because she has plans for them. Hoffel privately says to herself that she has plans for the Chanels as well.
Zayday and Munsch congratulate the Chanels for their work and Zayday suggests that now they see how fulfilling it is to help people. Instead, Chanel remarks on how easy it is to be a doctor. Chanel reports back to #3 and 5 that Munsch was so pleased with their work that she lifted their academic probation -- except for #5, who must work one last night shift alone. #5 is upset but Chanel explains that both she and #3 were asked out on dates (by Holt and Cascade, respectively), so Chanel #5, as the only one without a date, is the one who is stuck working.
During the night shift, #5 helps Catherine Hobart into a scalding hydrotherapy bath that locks once you get in. #5 locks herself in as well, to Catherine's trepidation, but #5 assures her that Chamberlain will be coming down to get them within the hour. Instead, a figure wearing the costume seen at the beginning of the episode taunts the two women with a knife, eventually cutting off Catherine's head.