‘Scream Queens’ Season 1 episode 4 spoilers: Synopsis and promo video tease Halloween, Hester’s plan and 1995 mystery [WATCH]

Lea Michele tweets joy over 'Scream Queens' premiere — Actress Lea Michele poses backstage at the 2015 Teen Choice Awards in Los Angeles, California, United States August 16, 2015. Reuters/Danny Moloshok

Some “Scream Queens” characters are determined to find the person accountable for the murders at Wallace University. The synopsis and promo video of “Scream Queens” Season 1 episode 4 titled “Haunted House” hint the accusation against Dean Cathy Munsch (Jamie Lee Curtis) and the investigation on the mysterious death at the Kappa Kappa Tau sorority house 20 years ago. [Spoiler Alert!]

The next episode’s synopsis reveals that a lot will go down as Halloween draws near. Zayday Williams (Keke Palmer) will make a shocking announcement in the new episode, which forces Kappa Kappa Tau sorority president Chanel Oberlin (Emma Roberts) to create a devious plan.

In the upcoming episode, Hester “Neckbrace” Ulrich (Lea Michele) will grow closer to Chanel’s boyfriend, Chad Radwell (Glen Powell). The promo video shows that Hester, who had a makeover in the previous episode titled “Chainsaw,” plans to own everything Chanel has, including Chad.

Security guard Denise Hemphill (Niecy Nash) will continue to search for the Red Devil killer at the university in “Scream Queens” Season 1 episode 4. Meanwhile, Grace Gardner (Skyler Samuels) and Pete Martinez (Diego Boneta) will visit a woman who has a connection to the 1995 mystery of the Kappa Kappa Tau sorority house.

The upcoming “Scream Queens” episodes are also expected to explore the mysterious disappearance of the dead bodies of Chanel #2 (Ariana Grande) and Kappa Kappa Tau sorority housemaid Ms. Bean (Jan Hoag). Series creator Ryan Murphy has confirmed on Twitter that fans can still see Ariana Grande as Chanel #2 in FOX’s new horror-comedy series.

Chanel #2 got killed off in a hilarious way in the pilot episode of “Scream Queens,” but the succeeding episodes still mentioned the character and showed her through an image she shared on Twitter. According to Variety, it is still unknown how Grande would come back in “Scream Queens,” but Chanel #2 could reportedly continue to appear in the show through flashback scenes, as a ghost or in dreams. The character could also reportedly still be alive and turn out to be the other Red Devil killer.

“Scream Queens” Season 1 episode 2 titled “Hell Week” has revealed that Boone Clemens (Nick Jonas) is not really dead and he is the Red Devil killer’s partner in crime. “Scream Queens” will return with episode 4 titled “Haunted House” on Tuesday night, Oct. 6, at 9/8c on FOX.