Two men venture into a forest where they stumble upon an abandoned church. Their exploration takes a dark turn when one of them is attacked in a horrific manner by a laughing man clad in a checkered jacket, resulting in a machete wound that leaves him incapacitated, while the other, Ty, flees in terror.
Meanwhile, we meet park ranger Roy McLean at his home, oblivious to the impending danger. A van filled with five adventurous teenagers sets off for a camping trip, but quickly loses its way despite Roy's stern warning to turn back. The group consists of Warren, a muscular blond; his bashful girlfriend Constance; the fun-loving Jonathon; his bold partner Megan; and the quirky camera aficionado Daniel. They encounter Ty, who is frantic and dirty, but dismiss his pleas to leave as they drive deeper into the woods.
Upon finding their campsite, the teenagers settle in, indulging in beer, food, and music, oblivious to the ominous presence lurking around them. As night descends, they eventually drift off to sleep while something sinister watches from the shadows. The next day, a visit to a nearby waterfall leads them to a young girl named Merry Logan (Katie Powell), whose sudden departure only heightens their sense of foreboding.
As Megan and Jonathon venture into the lake for a bit of skinnydipping, they are blissfully unaware of a lurking threat beneath the surface. When Megan feels hands on her, she believes it's Jonathon until she realizes he’s on the shore, prompting her to frantically swim to safety.
The group splits up to explore further, with Jonathon spotting Merry in the woods. He chases her, attempting to reassure her that he means no harm. However, she runs away in fear, leading Jonathon into a dangerous situation where he encounters the deranged twin, wielding a machete. The violence escalates as Jonathon's efforts to escape culminate in his fatal plunge into the river below.
Meanwhile, Megan and Daniel unintentionally stumble upon the church and an adjacent graveyard. After Daniel breaks his glasses, he mistakenly perceives an approaching figure as Jonathon. In a panicked moment, he pushes Megan out of harm's way, only to be fatally stabbed by the true predator. As Megan desperately tries to escape, she witnesses the chilling sight of the twins—one capturing their horror with a camera while the other prepares to attack her within the church.
Outside, Warren and Constance regroup at their campsite, only to discover Jonathon's lifeless body drifting in the river. They search for the others but find no trace, compelling them to return for the car keys that mysteriously vanish with Jonathon's body.
Ty finally encounters Roy and frantically reports the existence of the killer twins at the church. Determined to rescue the teenagers, Roy sets out on horseback, only to meet Merry's peculiar family—a father with a troubling past who, after the death of their mother, had an unsettling relationship with his own daughter that resulted in Merry's birth.
Amidst the chaos, Warren's quest for Jonathon's body leads him back to camp where Constance is attacked by one of the twins, forcing her to flee up a tree. In the nick of time, Roy arrives to shoot the attacker, prompting Warren and Constance to gather their belongings and escape as Merry navigates the woods in search of them.
The tense climax unfolds at their camp when the other twin ambushes Warren and attempts to kill Constance. In a twist of fate, Constance defends herself fiercely, ultimately overpowering the attacker. However, in a haunting moment of transformation, she mimics the peculiar sounds of the demented twins, leaving Warren bewildered and Merry watching from afar in horror. As the sun sets over the forest, the scene fades to black, encapsulating the chilling events that unfolded.
