MTV's new reality show, "Fear," plays off that sense of the unknown for both the people on the show and its viewers. "Fear" is what "The Blair Witch Project" would have been if it hadn't been so diluted by hype. Or "The Real World" without the exhausting relationship squabbles. Or "Survivor" set in hell.

Over on Fox Family Channel, "Scariest Places on Earth," hosted by Linda Blair, has an eerily similar feel to "Fear." On tonight's conclusion of the short series, an Illinois family spends the night in a haunted castle. During the debut episode Monday, four students and a university staff member explored an allegedly haunted room on a college campus, camera crew in tow. A demonic-looking face was clearly visible in the wood grain of a dorm room door; on the other side of the door, the room where a student committed suicide had been turned into a boiler room. Inside the room, barraged by a constant flow of loud noises, the group freaked out all at once and fled the scene.

Now, imagine being in that scary, haunted boiler room all by yourself, in the middle of the night, overtired, with only a dim light and crackling radio to guide you. That's "Fear."

The premise of "Fear," with its second hourlong episode debuting tonight on MTV, is simple. Six 20-somethings go to a crumbling, allegedly haunted place to search for paranormal activity. There, they have to complete a series of simple missions, or dares, like spending 15 minutes alone in a room or collecting a blood sample from a murder-stained floor. Complete all their tasks, and they get $5,000 each. Decide to quit, and they lose their money and another person must complete their dare. A computer in their central "safe house" guides them through their missions, selecting pairs or individuals to venture out and assigning remaining team members to serve as home-base navigators.

"Scariest Places on Earth" is scary enough, but its fear factor is diluted by constant narration and this disclaimer: "Some of the scenes depicted in this program were re-creations or dramatizations of actual or alleged events." So did the woman searching for the sasquatch-esque Jersey Devil on Tuesday's episode really hear a roar and run away, or was that a dramatization? "Fear" doesn't need dramatizations, because "Fear" is about the scariest thing on earth: nothing.

That's what makes "Fear" such a breakthrough show: It doesn't rely on traditional gimmicks for an all-too-temporary scare. Instead, it goes for the psychological thrill of the unknown and plays that off our empathy for real people -- people just like us. Then, with the hallmark of reality television, the show asks us to imagine ourselves in place of the cast. How would we feel trapped in a dark hallway? Could we peer under the tarp in a death chamber? As the scares keep coming, the MTV group is terrorized for an entire weekend -- and we are, too.

In the first episode, filmed at the abandoned West Virginia State Penitentiary, one of the players must visit the electrocution room. Lauren is the first person assigned to visit the room, which someone in an edited-in clip tells us still smells like burned flesh. She's supposed to pull the tarp off the electric chair and stay in the room for 15 minutes, but she can't bring herself to complete the task.

Meanwhile, in the Sugar Shack, a place where prisoners were beaten and killed by guards, Christina is flipping out, sobbing and begging "please God" because the light on her camera went out and "something's coming down the hallway." The rest of the team members abort their own dares and rescue Christina, who's had enough and wants to leave.

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