tell me the restof the movie

Short answer: Yes

Her car is taken to a mechanic who keeps photos of cars he has worked on. Matt sees a picture of the truck from the farmer's market. How he recognized it, I have no clue. The boys intimidate the mechanic into telling them where the owner is.

They go to the railroad tracks to search for him. They find a run down barn and a few other buildings and look around. Cam finds Nathan locked in a pen. He goes to find Amber who has accidentally stepped into a bear trap and passed out.

The crazy guy with the funky hair from the farmer's market sneaks up behind him and kills him with a shovel. Then he goes down to Nathan's pen and finds Matt. They fight and ultimately Matt is killed with an axe. Then the crazy guy goes after Holly who is running in the woods.

She runs to the sanitarium and breaks in with him following her. She manages to lock herself behind a cage and he tells her, "Your brother stays with me. You belong to your mother." This reveals that the crazy guy, who is badly burned, is their biological father who somehow survived the fire.

Amber wakes up and, with the bear trap still on her foot, hobbles to the sheriff's office.

In the sanitarium, Holly is captured and strapped to a gurney. The father goes to turn the power on and Holly escapes only to be captured again a short time later. In the process the father spills formaldehyde on himself and the floor. As he is giving her shock treatment to the temples, she pulls the matchbook from Jack Abel out of her pocket and finally lights it and ignites the formaldehyde. All of a sudden she is no longer strapped down (no clue how) and runs away while her father chases her while still on fire and finally dies.

The entire family is reunited, Amber goes to the hospital, Holly shuns the sheriff who is basically speechless at this point, and the end.