NOTE: This spoiler was sent in by Liono.

The movie starts off with an encyclopedia style meaning of what a Skinwalker is and the Navajo word for it. Following that, we get a small explanation in text form of a prophecy which tells of these Skinwalkers and how they are descendants of said Navajo Indians. One group wants to destroy this boy who, when he turns 13, will end the curse (aka, people turning into werewolves) and another group are trying to protect him because they want to be human again.

Now, we are brought to a man running around in a wooded area and there are bodies hanging dead from limbs. Quietly, he hides behind a tree and slowly pulls out a gun. We are still unaware of exactly what's going on. Suddenly, however, he is captured, and, he too is hung up, yet, still alive. We see a group of nappy biker looking punks, one who is an older female around her forties or early fifties. She's threatens the helpless man with a gun to find out where this boy is. He seems to not know anything. She then says that her and her gang will search every campsite, which are circled in red on a map she's holding, and find out where the boy is. It begins to get dark and she then shoots the man.

We are now taken to a log cabin in the woods where a guy and a small group of others are watching a videotape of a young boy playing with his toy train set. While watching they are talking about how it is only a few days away before the boys turns 13 (we get the impression that unlike the gang before, these guys are the good werewolves that want to become human again.) They shut off the television set and one guy, who seems to be a leader type tells everyone that it's time to go down to the basement where we see him strapping down the others (it's pretty much obvious that he's doing this to keep them from getting loose after they transform.) After securing everybody but himself, the lights go off. He assures everyone that it's probably just the fuse, in which he goes upstairs to fix the problem. Soon after, however, he gets ambushed by some people. Down in the basement the others aren't sure what's going on and one of the female members calls out the guys name, which we now find out is Ralph (we also learned just before he went upstairs that they are a couple). Afterwards, we see the biker looking guys come down into the basement with Ralph and threaten to harm them if they don't tell them where the boy is. The claim not to know and so Ralph gets killed.

Now we cut to a boy, Timothy, who seems to be having an asthma attack. His mom, Rachel is trying to help him calm down along with a family friend, Will. Finally, they get him calm.

The bikers go upstairs in the log cabin from before to watch the same tape that the good werewolves watched earlier to see if they can figure anything out. While watching, the leader known as Varek sees something in a mirror on the film. In it, it shows the reflection of a blue jacket, which backwards it reads Hugenot. Varek then tells the others that that's where he is and where they'll be going.

We cut back to Tim and his mom. She's sitting on his bed talking with him when she notices the moon and points it out to him. It's red, which to Tim and Rachel is a weird site (this obviously is a sign to show that Tim's birthday is coming up and what will become of the prophecy). The next morning we see meet various characters that or either friend or family members or Rachel in Tim's. We meet Jonas, who is the head honcho played respectively by Elias Koteas, his daughter Katherine, his mother Nana, Katherine's boyfriend Adam and the mailman, Doak. I should also mention that everyone knows about this prophecy except Rachel and Tim. In what looks to be a shed, Tim is playing with his train set along with Katherine. He says how he needs to fix his track, and tries to with an knife. Katherine asks if he's into blades now and Tim tells her it's an early birthday gift from his mom. Katherine says it looks old and used and he replies that it was his father's. Between all of this we get a scene where Tim is out in the fields flying a kite where Rachel and Jonas are watching form the side. She begins discussing with Jonas how all of Tim's life, after his father had passed away that they have all (meaning Jonas and his side of the family) been the ones raising Tim and that she feels like it's her turn. She tells Jonas that she made her decision to take Tim and leave to be more independent as a mother.

After this, Rachel and Adam load up in a pickup truck and head out to town. While doing so, a man who words at the coffee shop in town asks Rachel how's Tim doing, dealing with his asthma complications from the night before. She's tells him Tim is doing fine and then continues on her way in the truck. She tells Adam that the incident just happened and how nobody could sneeze without everyone in town knowing (we get the impression that everyone in town knows of the prophecy and are their to protect him as well).

Soon after, the gang of bikers, which consists of three men, Varek, Zo and Grenier, and one woman, Sonja, arrive in town on their bikes. They get off and begin to scout the town in search of the boy. Meanwhile, at the hardware store where Rachel and Adam work, Rachel begins to worry and she was expected Nana to bring Tim there by now. She tries calling the house, but, nobody answers.

After a while, we see Nana walking into town with Tim, and, as soon as she does, a hawk flies overhead and we see Varek staring at them. A few stares pass between them before both Nana and Varek draw guns and begin shooting at one another. At this time, the whole town begins to open fire at the four misfits. Tim runs and hides in the hardware store with his mom as the gunfire continues. The town sheriff gets shot and Adam yells out the word dad (the sheriff isn't a big part at all, but, I thought I'd tell you just so you'd know since Adam is). After some rounds, an old, clunky RV pulls up and the back doors swing open where Katherine, who's also called Kat, and Jonas start firing while the other good werewolves get in. Nana gets gunned down, and, knowing that there isn't hope for her, the RV flees. Nana gets back up and Varek tells her he just want the kid. He notices her slowly reaching for her gun, but, he tells her don't (we get the feeling that even though Varek is a "bad" werewolf that he still has some compassion because he doesn't want to have to kill Nana and earlier it didn't seem as though he killed the group of good werewolves her were strapped down in the basement). She pulls the gun out anyway while showing her big, sharp fangs and growling, and so Varek shoots her in defense, killing her.

Back in the RV, we get a shaky Rachel and Tim as Jonas tells them about the prophecy and how in a few days on Tim's thirteenth birthday the curse will end. It is starting to get dark, so Jonas, Kat, Doak and Adam strap in. Tim goes up front to talk with Will who is driving. Will tells Tim how he is not a werewolf, but how him and Jonas go way back.

Meanwhile, we're taken to a bar where two guys throw a young woman on a pool table to have their way with her when we see them noticing a woman sitting on a stool at the counter. One of them asks if she wants to join in and she turns around. It is Sonja in wolf form and she, along with the other three attack everyone in the bar eating on their blood and flesh.

Returning to the RV, we see the Jonas and the other growling and making noise as they are turning into werewolves. Tim hears the noise from up front, but Will tells him not to worry and that his mother is safe since she's in the back watching them turn.

We are now brought back to the bar where Zo and Grenier are still munching down while Varek and Sonja are making werewolf love. The next day, in the woods, they get ready and head back out in human form on their bikes.

Jonas and the others seem to be resting in a forest area where Tim comes up to Rachel and tells her that he isn't feeling good. Tim at this point is very sweaty and is very pale. We see a dream sequence where it looks as though beings of some sort are breaking into a house where humans are knocking them around, which is a sequence we see several times throughout the film. Tim wakes up after this nightmare in a hospital bed. Everyone's around to comfort him. Jonas, however, feels uneasy since they had to stop and tells Kat to keep an eye out around the back of the hospital and Adam to lookout on the roof. Soon, we see Tim's nurse going into the halls of the hospital where an injured person is being brought in by the ambulance. After being taken into a room, the nurse goes over to the "victim" who has a patch on her nose with a little blood on it. She goes over to take the patch off and we see that it's Sonja. She then goes into Tim's room dressed as the nurse. Rachel asks when they can leave and notices the nurse locking the door. Sonja turn around and attacks her. Kat, still out in the hall, hears the commotion and goes to the room where the nurse was and sees her lying dead on the hospital bed. Jonas calls Adam up on a walkie talkie and tells him to send the RV around. Grenier starts shooting at them and Doak gets behind Tim to protect him from the gunfire as the run out back. When they get outside, Doak tells Tim to go on and he falls to the ground as he is dying from the gun shots. Tim is crying and doesn't want to leave him but is taken to the RV. Grenier goes outside where they are and begins to open fire. Adam shoots back and kills him. We now see Varek come out along with Sonja, and he's holding Kat hostage. He tells Jonas he'll give her back in exchange for Tim, but, Jonas refuses the offer. This is also the scene where Rachel and Varek meet eye to eye for the first time since the begging of the film. She has tears running down her face and calls him Caleb. He looks back at her. We now find out that Varek use to be Caleb, Jonas' "dead" brother and Rachel's "dead" husband. This also means that he's the father of Tim. Some words are exchanged, but, realizing that this is not the time or the place, both good and evil sides part ways.

Rachel is mad at Jonas for keeping this secret and Adam is upset that Varek has Kat. Finally, they get to a safe place in the woods near a cave. Inside the cave, Jonas and Adam are talking. Adam is upset that Jonas doesn't want to do anything to help Kat since she is, after all, his daughter. Jonas tells him that it's too late and that going back after her would risk the safety of Tim. Adam then leaves Jonas alone in the cave where Jonas begins to cry for his daughter. 

Later than night, elsewhere in the woods, Varek and the others have Kat tied to a tree. It's becoming dark and Kat asks Varek why he's doing this. All of there eyes are bloodshot, which is a sign that they're beginning to turn. Varek lets Kat loose from the tree and he along with the others are holding Kat down.

We now skip to the next day. Everyone's waking up and getting ready to head on out when Jonas sees that Adam is missing. Deeper in the woods, Adam's running, looking for Kat when he comes up a body of water. He looks at the water and in the reflection sees something in the form a person. He then looks up and Kat is hanging crucifix style above the water and bloody, yet, still alive. Back at the RV Adam and Tim come from around the vehicle with Kat between them. Jonas goes over to Adam and punches him on the face saying that he could have lead Varek to them. Adam replies that he didn't see anyone.

They pull off with Rachel driving and Tim up front with her. In the back, Jonas, Adam and Will are talking to Kat asking about what happened. After they finish, Will straps Jonas and Adam in. Kat begins to act very weird, even more than she did when Adam brought her back. Jonas and Adam realize that she's turning and Jonas tells Will to quickly strap her in. But, it's too late and Kat breaks Will's neck. Jonas tells Adam to shoot her as he has a gun in his hands, but, he can't do it. She walks over to him and Adam tells her that he loves her. We then hear a gunshot and find out that Kat shot Adam, who is now dead. She begins to act upset and confused as though she's trying to fight the evil that is now in her. Jonas get free from his strap and rumbles a bit with Kat as she calls out to Tim to open the door to the front of the RV. Rachel tells him no. Kat then yells to Tim that Jonas is trying to hurt her and Jonas replies not to listen to her. Tim can't help it as he's close to Kat. He opens the door with a shotgun in his hands. Rachel tries to get him to shut it back, but, he doesn't. Kat then goes after him and we hear another gunshot. Kat falls down dead and we find out that Jonas shot her.

We are now brought to a scene where Jonas, Rachel and Tim arrive at an old mill. Soon it will be midnight which means Tim will turn thirteen and so they go in in hopes that they can be safe there. Jonas locks Tim and Rachel up in a small area and tells them to stay put and not let anyone in. Varek, Sonja and Zo arrive at the mill. The moon is once again red and everyone turns. Jonas and Zo meet first and begin to brawl until they get atop an area in the mill where Jonas knocks Zo off the side and down to ground. The fall kills him. Back where Rachel and Tim are hiding, they accidentally knock something over making a noise. Sonja notices the sound and hunts for them. Meanwhile, Jonas and Varek are now brawling, and, so far, Varek seems a bit stronger.

Back at their hiding spot, Sonja caves in on Rachel and Tim after jumping down on the top of the caged area. after getting a few swing around and scratching Rachel, knocking her out, Tim stands helpless and scared, but, Rachel gets back up and repeatedly shoots Sonja until she's dead.

We now zoom back to Jonas and Varek where they are still fighting. Not too long into the fight, Varek is "dead." Tim is looking at Jonas and crying. Even though Jonas is good, he's still a werewolf and can't control his bloodlust. He goes to attack Tim, but, before he can, Rachel shoots and kills him with her shotgun. Thinking that they are all dead, Tim and Rachel go to leave, but, Varek gets back up and goes to Tim. Tim holds his knife to Varek. Varek looks at him for a few moments right before biting him in the neck. A clock outside of the mill begins to ring at it is now midnight and Varek stops biting Tim. Rachel shoots him and he falls down to the ground. Slowly, Varek begins changing back to human form. Tim and Rachel go over to him where he is lying on the floor. We find out that the shot nor the fall killed him.

We now cut to Varek, Rachel and Tim getting a room at a hotel. Rachel sees a shadow and pulls her gun out. It's just a trick or treater dressed as the grim reaper. Rachel looks out the door and sees a sign showing that it's Halloween. She pulls her gun back and tells the guy that it's been a long night. The guy is scared and as Rachel and the others leave the main office to go to their room, Varek pats him on the shoulder.

Tim is now narrating, telling that while his blood will end the curse, it wouldn't be as easy as they hoped. We see Rachel drawing blood from him. To the left of Tim is table with syringes filled with his blood and bullets that Varek is putting Tim's blood in. A man knocks at the door. Varek opens it and he tells him he's there for the cure. In his narration, Tim tells how that for some he will save them from the curse, but, for other's (at this time we see a werewolves eye [most likely turning]), he will be the end of them.