Hell of a Summer ending explained: Who is the Devil Slasher?

Hell of a Summer is a 1980s style horror comedy film written and directed by Finn Wolfhard and Billy Bryk. The film marks the directorial debut of Ghostbusters: Afterlife stars, and tells the story of a group of camp counselors getting massacred by a slasher wearing a devil mask during a preparatory weekend before summer.

Disclaimer: The following article contains the author’s opinion and spoilers from Hell of a Summer. Reader’s discretion is advised.

At the end of the film, it is revealed that there are not one but two killers in the camp, from among the counselors themselves. Two of the earliest victims of the mystery killer, dubbed Devil Slasher, have been camp counselors Demi and Mike. However, it turns out that they faked their own deaths and have been going around killing their peers.

Running for 88 minutes, Hell of a Summer premiered at the Toronto International Film Festival on September 10, 2025. Neon secured distribution rights of this film and released it in theaters on April 4, 2025. In addition to Wolfhard and Bryk, the slasher movie features Fred Hechinger, Abby Quinn, D'Pharaoh Woon-A-Tai, Pardis Saremi, Rosebud Baker, and Adam Pally.

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How does the Devil Slasher take out the camp counselors in Hell of a Summer?

Hell of a Summer opens with the death of Camp Pineway owners, John and Kathy, at the hands of a masked murderer. John is killed with an acoustic guitar shoved down his throat while Kathy takes a knife to the head. Their absence makes 24-year-old Jason Hochberg, the leader of a group of 11 counselors who arrives ahead to prepare for the upcoming summer camp.

Jason has difficulty connecting with others because of his age, and the fact that the group includes his ex-girlfriend, Claire. They split up when the night falls. While conducting a routine check, Jason discovers Demi, a popular social media influencer, slaughtered inside her cabin. By the time he brings the group together, Demi’s body disappears. However, the blood on her bed sends everyone panicking.

Those attempting to flee the camp are not able to start their cars. In this commotion, counselors Mike and Miley disappear inside the mess hall. The latter's decapitated head is later found in the freezer. A fourth, Ari, is abducted by the killer when alone and stabbed with a knife coated with peanut butter, since he is allergetic to the substance.

The remaining counselors hold Jason responsible for the killings and tie him up. He is saved by Claire, and the duo runs off into the woods. While Claire wants to escape, Jason gets adamant about saving others, and head back. Meanwhile, counselor Noelle gets stabbed and her head bashed in with a rock.

At this moment, it is revealed that Demi and Mike have faked their deaths, as they both appear dressed identically as the killer. In the final showdown, Ezra gets murdered with an axe, while Bobby fights back and slit’s Mike’s throat. Meanwhile Claire finds Demi trying to kill Jason and shoots an arrow through her eyes, which effectively eliminates the killers.

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What was Demi and Mike’s motivation in Hell of a Summer?

Demi and Mike are driven to kill their fellow camp counselors in Hell of a Summer simply to get famous. True to the campy nature of the film, the reasoning behind this massacre is seemingly kept shallow by the writers. As a social media influencer, Demi's love for going viral is established early in the film, which leads her to going on a one-night hunting spree.

In case of Mike, the motivation becomes simpler as he only seems to have followed Demi’s orders in Hell of a Summer. They improvise their plan as they realize framing Jason as the killer and themselves as brave survivors will work better for them. However, neither manage to make out of the camp alive at the end.

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