The movie starts out in 1980 with Pamela Voorhees chasing the final surviving victim of the original Friday the 13th killings. She blames the counselors for Jason's death and is about to stab the last girl when the girl picks up a machete and cuts off Mrs. Voorhees' head before running away. Meanwhile, a young Jason is watching from above in a tree and jumps down to retrieve his mother's body and the machete.
It skips ahead to present day where Whitney, her boyfriend Mike, Amanda, her boyfriend Richie, and Wade are hiking through the woods of Crystal Lake in search of weed growing somewhere. They set up camp for the night and Wade tells them the story of Jason and Crystal Lake, which no one believes. Whitney and Mike take a walk, while Amanda and Richie have sex, leaving Wade to wander by himself where he stumbles upon the weed and Jason, who quickly kills him. Amanda and Richie hear someone in the woods, so Richie leaves to check it out, leaving Jason to grab Amanda in her sleeping bag and tie her up above the campfire, leaving her to burn inside. Richie tries to run to help her, but gets his leg caught in a bear trap. Meanwhile Whitney and Mike are exploring a run down house in Camp Crystal Lake. They find Mrs. Voorhees' necklace with a picture of herself in it, leading Mike to comment on the resemblance between her and Whitney. In another room they find Mrs. Voorhees severed head. Jason begins attacking them, stabbing through the floors and cutting up Mike before pulling him through the floor completely. Whitney runs to find Amanda dead and goes to help Richie before Jason appears behind her, slicing his machete through Richie's face. Jason runs towards Whitney about to slice her and the scene ends.
It cuts to Whitney's brother, Clay searching for his sister in a few different places around the Crystal Lake area, including a barn where a hick works and a convenience store where Clay runs into some college kids including Trent and his girlfriend Jenna. A police officer stops Clay, telling him that the police have searched everywhere and Whitney and her friends are not in the area anymore, suggesting he look elsewhere. Jason stops by the barn where Clay was and slices the hick's neck with his machete in the attic after the guy pulls off his knapsack, where you can quickly view Jason's deformed face. Jason then finds the hockey mask amongst other garbage and puts it on.
Meanwhile the college students, Trent, Jenna, Chewie, Bree, Lawrence, Nolan, and Chelsea, pull up to Trent's parents' cabin in Crystal Lake to party. His family hunts and so there are various animals mounted on the walls. Nolan and Chelsea leave the group to take out Trent's boat and water ski topless, until Jason shoots Nolan through the back of the head with an arrow while Chelsea is riding. The boat then runs into Chelsea causing a wound on her head, creating more panic when she sees Jason on shore looking at her. She swims to a dock and hides underneath with Jason above her, who then stabs through the dock and right into Chelsea's head. Clay stops by Trent's cabin continuing his search for Whitney, and again runs into Jenna who takes a walk with him to the other side of the lake. Whitney is also shown imprisoned in Jason's system of tunnels, which seem to spread all over Crystal Lake, explaining how he appears out of nowhere. The tunnels also contain bells, which ring when people set off the trip wires he has set up around the woods.
When night falls, they find Jason's house, but hear him approaching so hide under some canoes, leaving Clay's backpack in sight. Jason walks to where they were at with the hick's decapitated body over his shoulder. He drops the body in front of Clay and Jenna and then turns on spotlights and begins overturning the canoes. Clay and Jenna run back to the cabin. Back at Trent's cabin, Chewie, Lawrence, and Bree are partying when Chewie accidentally breaks a chair trying to impress Bree. Trent gets pissed and tells Chewie to go to the tool shed to grab tools to fix it. Trent and Bree then go upstairs to have sex. Chewie goes to the shed, finding some good liquor and sports gear before running into Jason. He grabs a screwdriver to defend himself, but Jason takes it and slowly stabs him in the neck. Clay and Jenna make it back to the cabin to warn everyone and call the police. The remaining members, Clay, Jenna, Lawrence, Bree, and Trent try to figure out what to do, when Lawrence grabs a frying pan and bat to look for Chewie. He goes into the same shed and Chewie's body falls from above, dangling in front of him. Jason appears behind Lawrence, who puts up a good fight, before running out of the tool shed. Jason grabs a double-sided ax and throws it right into Lawrence's back. The people at the cabin hear Lawrence's cries for help, but Clay warns them that Jason is just using this to lure the friends out of the cabin. Jason picks up Lawrence slams his body into the ground, forcing the ax out the other side. Trent runs upstairs to get a gun with Bree following. She goes into the bathroom and sees the window is open, so she checks behind the shower curtain. Jason is behind her and slams her body into a set of deer antlers mounted on the door. The same police officer that spoke to Clay earlier arrives at the cabin, but before he can enter, Jason jumps off the roof behind him and stabs him in the eye and through the door with a fire poker, pinning the cop to the door. Clay and Jenna run upstairs and meet Trent, who finds Bree's dead body, and all three of them run out of the house. Trent jumps into the cop car, but before he can drive off, Jason throws Bree's body on the windshield. Clay and Jenna run in one direction, while Trent runs a different way, eventually losing his gun. He comes upon the road when a pickup truck stops. The driver says nothing and makes no movement besides stopping his truck. Paranoid it might possibly be Jason driving, Trent hesitates to walk towards it until too late, when Jason shows up behind him and stabs him through the chest with a machete, before impaling him on the back of some poles on the truck, which then takes off.
Clay and Jenna make it to Jason's house again, this time hearing screams below. They make their way into Jason's tunnels and find Whitney. Clay breaks Whitney's chains with a hammer as Jason appears, making his way towards them. The three flee down the tunnel systems, coming to hole only one person at a time can fit through. Whitney goes first, then Clay, who is about to help Jenna through when a machete bursts through her chest. Clay and Jenna stare at each other helplessly before Jason tosses Jenna's body and continues after Clay and Whitney. The tunnel exits inside an overturned school bus where Clay and Whitney escape after a close encounter with Jason, who then retreats back inside the tunnel system. Clay and Whitney make it back to the barn from before, with Jason once again attacking. Clay and Jason struggle for a little as Clay wraps some chains around Jason before Jason gets the upper hand, attempting to shove Clay's face into giant electric wood chipper. Whitney saves Clay by confronting Jason as his mother, and then throws the chains into the spinning metal spikes, which hold Jason down as Whitney stabs him in the chest with his machete.
The final scene is of Clay and Whitney throwing Jason's body into the Crystal Lake, along with his mask and machete. Clay goes to comfort Whitney, just as Jason bursts through the dock and grabs onto her.
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