It's a classic set-up with a twist: Five urban college kids head to an isolated cabin (so isolated there are no roads leading to it) for a post-finals break. Paul (Rider Strong) and Karen (Jordan Ladd) have been friends since they were kids, but Paul would like for them to be lovers.

Jeff (Joey Kern) and Marcy (Cerina Vincent) are an overly amorous couple, and fifth wheel Bert (James DeBello) is an obnoxious party animal.

Things go well until that night when a grotesquely ill vagrant shows up at their door begging for help. The kids are more concerned with self-preservation than altruism and, in the heat of the moment, they bludgeon the man and inadvertently set fire to him before sending him on his way.

Their problems are just beginning, however, as the group discovers they've been exposed to an aggressive flesh-eating virus. Isolated and with no one to turn to (the locals are a suspicious and xenophobic lot), they turn on each other.

In lesser hands, it might make a movie-of-the-week at best, but director and co-writer Eli Roth has crafted a squirm-inducing exercise in paranoia that ranks right up there with John Carpenter's "The Thing." Roth takes time to develop his characters before putting them through a hellish situation and upping the stakes in a horrific comedy of errors. Better yet, he does so without resorting to the silly, post-"Scream" self-consciousness or lazy storytelling that currently plagues the genre.

"Cabin Fever" harbors no pretensions about itself or its influences — it wears "The Evil Dead" and "Last House on the Left" proudly on its sleeve — and Roth takes things just seriously enough to deliver the goods while serving up some twisted laughs along with the tension.

While it's very generous with gore (viewers with delicate sensibilities will want to avoid "Cabin Fever"), what makes Roth's film truly disturbing is the cultural clash it depicts and the way his characters' collective humanity goes out the window as the disease spreads. Like some of the films that inspired it, "Cabin Fever" is, more than anything, a well-timed examination of moral ambiguity.