Twenty years after a mysterious death rocks Wallace University, another murder takes place.
When anti-Kappa Dean Cathy Munsch decrees that sorority pledging must be open to all students, and not just the school’s silver-spooned elite, all hell is about to break loose, as a devil-clad killer begins wreaking havoc across the campus.
Chanel finds a new project in Hester, Chanel #3 confesses a secret and Grace and Zayday uncover a surprising connection between two fellow students. Meanwhile, Denise sets her sights on one of the Kappas, and Dean Munsch appoints a new Wallace University mascot as Chad and Earl Grey lead the fraternity on a witch hunt for the Red Devil.
As Halloween approaches, Chanel creates a devious plan after Zayday makes a shocking announcement. Meanwhile Grace and Pete pay a visit to a mysterious woman with ties to Kappa's past. Also, Hester grows closer to Chad, Denise continues her search for the red devil killer and Dean Munsch does everything in her power to keep Wallace University open.
With Halloween just days away, Dean Munsch makes an announcement affecting the campus and, specifically, Chanel's plan to throw a pumpkin patch party in support of her Kappa Kappa Tau presidential campaign. Meanwhile, Grace and Pete lead a search party for a missing friend, which steers them closer to the Red Devil than ever before, and Chanel #3 and #5 learn what life would be like without Chanel.
In an attempt to protect herself from the killer, Chanel makes a surprising decision, which leaves Zayday in a position of power. To stay close to each other, the girls of Kappa Kappa Tau host a slumber party, but when a shocking discovery is made, not everyone will survive the night.
Dean Munsch is left in a desperate situation when a shocking event leads her to come face-to-face with her ex-husband's mistress. Meanwhile, in an attempt to determine who the Red Devil killer is, the Kappas use a Ouija board to communicate with Chanel #2 from beyond the grave and learn of a wicked plot against one of their own.
Grace enlists Chanel’s help to learn more about KKT’s past, and ends up realizing she might not be so different from her nemesis after all. Dean Munsch goes “psycho” when she becomes the latest target of the Red Devils. Meanwhile, Denise becomes the new house mother of Kappa House and a shocking figure from the past returns.
Denise does little to calm the Kappas' fears when she spins a terrifying ghost story. Meanwhile, Hester's shocking announcement pushes Chanel to the edge, and a familiar face returns to campus as the Red Devil claims another victim.
Chad takes Chanel to his family home for Thanksgiving, where she meets his brothers, Brad and Thad, as well as his parents. However, an uninvited guest throws the holiday into chaos. Meanwhile, Dean Munsch gathers the survivors at Kappa House, but dinner quickly explodes into accusations of who among them is really the killer. Then, the Red Devil carves up a deadly main course as another victim falls.
After the horror-filled events of Thanksgiving, the Chanels decide to celebrate their favorite holiday -- Black Friday, but the Red Devil has plans to stop their shopping spree. When the Kappas conclude that Dean Munsch is the killer, they set a plan in motion to stop her once and for all. Meanwhile, Denise lands yet another job, Chad offers Pete a chance to join the Dickie Dollar Scholars and someone confesses to being the murderer.
Shocking confessions are made as the Red Devil is finally unmasked and the killer revealed.