Denise Hemphill is introduced by Gigi Caldwell to The Chanels after Gigi hires her to protect Kappa Kappa Tau from the Red Devil. Denise says that with her attention, the Kappa girls have nothing to fear about. She clarifies that she is a security guard, not a police officer, so she does not have authorization to carry a firearms. She proceeds to say the Secure Enforcement Solutions three-step program:

1) Scream Denise Hemphill’s name real loud. 2) Call 1-866-KLJ-0199. 3) Get the hell out of there. Run away real fast. And when you get to a place you deem to be safe, call 1-866-KLJ-0199.

Later, Denise is keeping an eye on the Kappa house outside in her car. A fellow security guard, Shondell , who works at the Best Buy parking lot, comes to visit with hamburgers. Subsequently, they are both sleeping in the car and Denise later hears a scream from the Kappa house, so she wakes up, leaves the car, and runs into the house to protect the girls, leaving Shondell alone. When Denise enters the house, Chanel Oberlin explains that a person in a Red Devil costume attacked her upstairs. The girls decide to go upstairs to catch the killer, assuming he or she still there, and Denise tells them that the last thing they should do is go upstairs where the killer presumably is. However, the girls go upstairs anyway. Denise returns to the car for her inhaler and finds Shondell dead with a knife stuck in her throat. Denise screams, starts the car and drives away. However, she stops momentarily to push Shondell's body out of the car, then continues to drive away. At the end of the episode, Denise and Chad Radwell appear at the Kappa house and interrupt the dinner to announce that Shondell has been murdered, her corpse has disappeared, and Boone is dead as well.Zayday and Grace look for Chanel #2 's room, and find her door with a "Do Not Disturb" sign on it. When they find a stain on the floor, Zayday assumes it's blood and Denise pops in and says, "Of course it's blood." She sprays luminal on the stain and confirms that it's definitely blood. Then, she shows Grace and Zayday Chanel #2's last tweet from Pilot , where she stated that the Red Devil was killing her. Grace, unconvinced, then says that #2 is still posting pictures on Instagram and shows one to Denise. Grace and Zayday decide to go visit #2's parents' house in California, with Denise tagging along.

The next day, Denise, Grace and Zayday drive to the house and talk with #2's parents. Grace informs them that a serial killer is loose in the campus and shows them Chanel #2's last Instagram post, to which Denise says isn't a good picture. She also thinks someone might be posting them for her. Her parents then says she was in rehab and became happy when she met Chad, who even had Thanksgiving with her family and wrote her a letter.

That night, Denise asks Zayday to join her in her car. Denise then handcuffs Zayday and claims that she is the killer, showing evidence including a chainsaw under the bed. Zayday retaliates and tells Denise that the chainsaw was given to her by her grandmother for defense against the killer. Denise ends up letting her go and says she got her eyes on her.

Denise rushes into Kappa house and tells Detective Chisolm, Wes and Gigi about the attempted murder of Caulfield and says when they get fingerprints from the chainsaw that they will find Zayday's.

When leaving the university, Grace receives a text from Pete to meet him at 53 Shady Lane. When she arrives, Pete scares her and soon Earl and Zayday scare him. When Grace asks what they are doing there, Zayday says she is having the haunted house charity there. Denise appears, startling them and says the house is haunted and tells them the story of 'The Hag of Shady Lane', the former resident of the abandoned shack, who took care of the bathtub baby in 1995.

Assuming Zayday is responsible for the murders, Denise refuses to allow Zayday to throw the party, but later backs off when Zayday reveals that she knows Denise was a former Kappa reject in 1988, and thus a possible suspect.

In Munsch's office, Cathy and Denise talk about their experience with sleeping with Chad until Grace, Pete, Gigi, and Wes enter the room and urge the two to help find Zayday. Cathy says she hired an investigator from Secure Enforcement Solutions, which is Denise, who is still convinced that Zayday is the killer and faked her own abduction.

Grace, Pete, Wes, Gigi, and Denise find The Red Devil's secret lair, where the Red Devil turns the power off leaving them in total darkness. Gigi, however, manages to taser the Red Devil. When the power turns back on, Denise runs to the others to tell them. When they return, Gigi says the Red Devil got up and hit her in the head with a baseball bat and escaped down a laundry chute.

At Dickie Dollar Scholars, Earl confronts Chad about him sleeping with Dean Munsch and Denise, which he happily confesses to and announces they should have a pantie raid at Kappa.

When the power goes out in Kappa house, Chanel calls Chad with her satellite phone as the phone lines are down and tells him to rescue them. While asking, he tells her he was coming over anyway and confesses about sleeping with Dean Munsch and Denise.

Denise becomes increasingly determined to prove that Zayday is the killer, especially when Chanel #3 offers

her 3 million dollars if she accomplishes this. Soon after, she goes to Jennifer to ask if she knows anything that could be used as evidence. Jennifer tells her about Zayday being bullied at school. Zayday, having overheard what Jennifer said, becomes enraged and tells Denise to stay away from her. Later, Denise appears with Chanel #5's clothes and becomes the "Kappa-House-Momma." (her clothes can be seen from Chainsaw, when Hester gets a makeover) That evening, Jennifer is murdered by the Red Devil. As a result, Dean Munsch shuts down all campus operations.

After Chanel #3 tells Denise and the Chanels that she saw Boone's ghost, "Momma" Denise tells a Japanese ghost story by the fireplace, which is about a Japanese schoolgirl sitting on the toilet and being pulled into the toilet by a monster. The Chanels tell her that it makes the situation worse. She tells another one about a Japanese schoolgirl sitting on the toilet in a stall seeing red toilet paper on her left and blue on her right. Picking red will get your throat slit and blue will get you strangled until your face turns blue.

After telling the story, Denise enters a stall in the house and sees red toilet paper on her left and blue on her right. The Red Devil's hands appear at the top of the other stall, Denise looks up and sees the killer peeking over, she screams as the killer climbs over. There's a struggle as the killer grabs Denise by her hair and tries to dunk her head in the toilet, but she manages to fight back, causing the killer to bang their head and Denise to escape.

She rushes to the Chanels and locks the doors with her handcuffs. Hester tells them another ghost story similar to "The Killer in the Backseat." After telling the story, Chanel #5 then decides to leave.

When the Chanels are attacked by the Red Devil in the mall, they run down the escalator and see the Red Devil and see a half closed shutter and run towards it and go under, but Chanel stays behind thinking the killer is Dean Munsch. When face to face, she gets shot in the shoulder with a crossbow, when the killer reloads and aims, Denise and two cops appear. It's revealed that Denise is now chief of police after the homicide department were all fired due to no leads in the Red Devil killings. While Denise talks too much, the killer shoots one of the cops and escapes.

Denise has the Chanels arrested after Hester frames them for being the Red Devil killers.