NOTE: This spoiler was sent in by Priya
Kate Beckinsale and Luke Wilson star in this movie as married couple David and Amy Fox. The movie opens to show them driving late through the night. Amy, who has dozed off, is jolted awake when David swerves to avoid a raccoon. Irritably, she asks where they are. David informs her that the interstate was blocked up so he decided to take some side roads. They argue a little bit, and David brings up the topic of their son (who died in an accident), which shuts Amy down completely. It's clear that Amy has trouble facing her emotions regarding the death of their son.
Soon enough, their car begins to cough and sputter. The couple wind up at a gas station in an old, deserted rest stop. They begin arguing again until a young mechanic (Ethan Embry) pops up and takes a look at their car. He also directs them back to the interstate. Amy and David thank him for his help and they get on their way.
About 2 miles down the road, their car completely breaks down. They have no choice but to hike it back up to the rest area. They go into the old motel and ask the front desk manager where they can find the mechanic. He tells them that the mechanic has gone home for the evening and won't be back until morning. He offers them a room to stay for the night. Amy wants to go back and sleep in the car, but David doesn't want to walk the 2 miles back to it. They decide to take a room. The motel manager offers them the "Honeymoon Suite" for only five dollars more, but they decline. Being friendly, he says he'll give it to them anyway, for the same price as a regular room.
The room is disgusting. After seeing how filthy the bedsheets are, Amy says she'll sleep in her clothes. She goes into the bathroom and finds large roaches scuttling around. All of a sudden, they hear some deafening thuds against the front door. When they open it, there's no one there. This goes on for some time, finally driving David to get the motel manager to come check it out. He finds nobody else around.
David finds some videos on the table and pops one into the VCR. The video shows a man getting stabbed and killed by two masked men. Amy complains to David to turn off the video, because she's trying to go to sleep. David pops in another video, which is of three women getting attacked, raped, and killed by the same two masked men. David looks at the bed and curtains in the motel room and realizes that they're in the same room that the videos are taped in. Amy, who was watching the tape from behind him, asks if it's the same room.
David checks a ceiling vent and sees a video camera recording them. Amy starts to panic and demands that they leave, but David says that the killers are watching them and will probably kill them if they try to escape.
They try to use the room phone, but find that the line is dead. While Amy tries to open a tiny bathroom window, David sneaks outside to use the payphone. He calls 9-1-1 and explains that he and his wife are in danger of being killed. The 9-1-1 operator says something like "Remain calm. Help will be on the way, Mr. Fox". David realizes that he never told the operator his name. He quickly hangs up and jumps out of the phonebooth, right as a car smashes into it. He runs back to the motel room, with the car right behind him.
Once inside, he begins watching more of the snuff tapes, looking for clues that might help them. He sees that the two masked killers always appear suddenly, and that they come out of the bathroom. He goes into the bathroom and finds a trapdoor under the rug. He and Amy get inside it and crawl through underground tunnels. They pop out in a small office room where there are many TV screens, each hooked up to a different camera in their room. Amy uses the phone (this one has a real line) to call 9-1-1 again. She hears a noise, and she and David duck back under the door.
The motel manager storms into the room and sees that the handle on the door has been moved. He yells at the two masked men to find them. The men get into the underground tunnels and begin hunting David and Amy.
The couple manage to find another opening that takes them to the rest stop's supply store. They come out and barricade the trapdoor by pushing some shelves down onto it.
Headlights shine through the window, and when they look out, they see a sheriff's car pulling up. Amy wants to run out to him, but David warns that he could be in on it. The sheriff talks to the motel manager, explaining that he got an emergency call from the location. He decides to take a quick look around. He goes through some empty, musty rooms until he comes to a room where a TV is on. A snuff film is playing on the TV. The sheriff realizes that the film was made in the room he's standing in. He draws his gun and rushes back out.
When Amy and David see how scared he looks, they run out to him. He yells at them to get in his car. All three of them pile in, but when the sheriff tries to start the car, it doesn't work. He realizes that the wires have been cut. He gets out of the car and opens the hood, but the masked men get to him first and kill him.
Amy and David scramble out of the car and race back to their room. David finds a little trapdoor in the ceiling, where he makes Amy hide. Before he can do anything else, the two men come in and stab him in the stomach. Amy watches from above, but can't do anything to help.
The men drop David to the floor and leave to look for Amy. She slides off of the trapdoor and leaves the room. She sprints across the courtyard, with the masked killers behind her, and sees her car parked nearby. She jumps in and starts driving, but one of the killers jumps on top of the car and breaks into the sunroof. She loses control of the car and crashes into a motel room, killing both masked men (one was in front of the car, the other was halfway in the sunroof). She gets out of the car and makes her way over to the front desk. She grabs a six shooter hanging in a display, but the hotel manager appears and kicks it out of her hand. The two of them go at it, beating, punching, and strangling each other. The manager just about beats Amy senseless, when she manages to get ahold of the gun on the floor. She shoots him a few times in the chest, killing him. She runs out to where David is lying, from the night before. She turns him over and he opens his eyes.
The movie ends with her sitting there cradling him.