In the summer of 1984, the quaint coastal town of Cape May, Oregon, becomes the center of a chilling mystery as it grapples with the elusive threat of the "Cape May Slayer," a notorious serial killer linked to the unexplained disappearances of 13 teenage boys over the preceding decade. Among the town’s residents is Davey Armstrong, portrayed by Graham Verchere, a curious and perceptive fifteen-year-old whose father happens to be a journalist uncovering the unsettling tale. Intrigued by the ongoing terror, Davey harbors a growing suspicion that his seemingly genial neighbor, Wayne Mackey, played by Rich Sommer, a well-liked police officer in the nearby Ipswich, is in fact the notorious slayer.
Davey's conspiracy theories initially arouse skepticism among his band of friends: Dale "Woody" Woodworth, Curtis Farraday, and Tommy "Eats" Eaton, portrayed by Caleb Emery, Cory Grüter-Andrew, and Judah Lewis, respectively. They dismiss his claims as the whimsical fabrications of a teenager known for weaving urban legends. Nevertheless, when Davey witnesses a boy inside Mackey's home who later appears as a missing person on the back of a milk carton, their perspective shifts dramatically. The four boys unite, determined to delve deeper into the mystery that looms over their town.
As the burgeoning detectives embark on their investigation, they meticulously document Mackey's daily life, leading them to uncover a series of suspicious behaviors. Mackey's routine involves purchasing gardening tools and soil in bulk, arriving home with a mysterious duffel bag daily, and partaking in late-night jogs that raise eyebrows. During a game of manhunt, they stake out in front of Mackey's house, leading to a tense confrontation when Mackey spots Davey clandestinely placing a walkie-talkie near his window, increasing Davey's concerns of being discovered.
The group’s investigation intensifies when Woody and Farraday stumble upon unsettling evidence—a second vehicle and canisters filled with sodium hydroxide tucked away in a self-storage unit owned by Mackey. Meanwhile, Davey and Eats make a shocking discovery: a bloodstained shirt linked to the missing boy, hidden within the confines of Mackey's garden shed. When they present this evidence to Davey's parents, their attempt is met with outrage, resulting in a grounding for Davey as they accuse the boys of vandalism rather than appreciating their alarming findings.
In spite of being grounded, Davey sneaks out to meet Nikki Kaszuba, played by Tiera Skovbye, who is not only a friend but also the shared crush among the boys. She pleads with Davey to abandon his investigation, fearing for his safety. The next day, a twist occurs when Mackey visits the Armstrong household, attempting to corroborate his innocence by calling his nephew, but the call falls flat when it goes unanswered. This revelation awakens Davey’s instincts once more, igniting his resolve to dig deeper into the case.
As events unfold, a suspect is apprehended in connection with the Cape May Slayer case, and ironically, Mackey plays the role of the arresting officer. This twist frustrates Davey, prompting him to devise a plan to break into Mackey's home during the 1984 Cape May Festival. In a pivotal moment, Farraday, acting as a lookout, soon learns that Mackey's bags of soil were part of a legitimate city beautification project, leading Eats and Farraday to abandon their posts, further complicating the situation.
Determined to uncover the truth, Davey, Woody, and Nikki sneak into Mackey's home equipped with Mr. Armstrong's video camera, venturing into a locked room in the basement that eerily resembles Mackey's childhood sanctuary. The horror escalates as they discover a desiccated corpse of the missing boy lying lifeless in the bathtub, accompanied by another recent victim still clinging to life. The reality dawns on them: Mackey is indeed the Cape May Slayer they have been chasing.
Realizing the gravity of their findings, the boys rush to present the terrifying footage to the Ipswich Police Department, resulting in an All Points Bulletin being issued for Mackey. However, the nightmare isn’t over. Later that night, Mackey retaliates by abducting Davey and Woody, disposing of them on a desolate offshore island where he introduces a chilling game of manhunt. In a terrifying chase through the wilderness, the boys stumble upon a graveyard of corpses, highlighting the horrors they must navigate.
In an act of bravery, Davey distracts Mackey long enough for Woody to escape to their cruiser, only for tragedy to strike when Mackey overpowers Woody and fatally slashes his throat. Facing the ultimate terror, Davey finds himself cornered, yet Mackey, in a moment of grim mercy, chooses instead to leave Davey alive, instilling in him a dread that will forever haunt his thoughts, perpetually waiting for Mackey's return.
Eventually rescued and returned to a semblance of normalcy, the weight of the trauma lingers as Davey takes on his paper delivery route once more. Each house he passes tells a story; the abandoned residence of a boy who went missing, Eats's home marked by turmoil and strife, and Mackey's house, now encircled with police tape, serving as a bleak reminder of the terror. As he unfolds a newspaper, his heart sinks at the headline that starkly reads: the Cape May Slayer remains on the loose, showcasing that the nightmare may not be over yet.
