"Hostel" was the smartest, deepest and most effective horror film of 2006, an uncompromisingly merciless thriller with an unthinkable premise—an organization in Eastern Europe that traps out-of-towners and serves them up to customers who have paid money for the experience of killing someone—made all the more frightening because it was actually plausible. Besides that, the movie provocatively touched upon any number of thought-provoking themes and notions—Ugly Americanism, xenophobia, topographic dislocation, the mirroring of one's exploitative desire for sexual gratification with that of another's murderous impulses—that raised it above the level of just a typical, violent genre pic. At the masterful helm was writer-director Eli Roth, who cemented with only his second big-screen effort that he was one of the most knowledgeable and skilled filmmakers working in the horror arena.

With "Hostel: Part II," conceived as the second and final entry in the series (no trilogies this time, one can hope), Roth may not have detectably grown as an auteur, but he certainly has defied expectations. At first glance, the film looks as if it will be a retread of the original, with the only difference being the change in sex from male to female for the three central protagonists. Roth flirts with this presumed assumption of his audience, but little by little he turns the formula on its head. In superficial ways, yes, "Hostel: Part II" resembles "Hostel." Tonally, however, the difference between them is incalculably vast. Whereas the first film began as a college kid's wet dream and ended as a nightmare, "Hostel: Part II" is cloaked in a blanket of dread and darkness from frame one. Even the lighter moments in the first act seem like taunting harbingers of doom.

Beth (Lauren German) and Whitney (Bijou Phillips) are American art students studying abroad in Rome who hop a train to Prague for a getaway weekend of partying and frivolity. Tagging along with them is classmate Lorna (Heather Matarazzo), a somewhat geeky outsider missing her home in Baltimore and hoping to fit in. After befriending local art model Axelle (Vera Jordanova) on the train, they alter their vacation destination with the exotic promise that Slovakia's natural hot springs are unlike anything they have seen before. Anyone who knows anything about the plot of the predecessor—or at least takes heed of the opening scenes involving the first movie's survivor Paxton (Jay Hernandez)—will have a pretty good idea what's coming. Sure enough, Beth, Whitney and Lorna check into the same infamous hostel and are lured to a nearby masquerade harvest festival. Several men show a liking to the trio of gals, and only Beth is cautious enough to realize the dangers of being left alone in a foreign country.

As these girls' story plays out in ways that range from predictable to clever to shocking, "Hostel: Part II" takes a step behind the curtains of the operation. Simultaneously detailing the reality-based ins and outs of the deadly business and the trek two new American clients, Todd (Richard Burgi) and Stuart (Roger Bart), go on when they receive the highest bids for Beth and Whitney, the film fills in all of the gaps and questions left by the original and partially tells the story from the bad guys' points-of-view. This brave plot decision on director Eli Roth's part initially appears to be risky, since the unknown is often scarier than having things spelled out. With just the right touch, though, Roth is able to build upon and enrich the ideas he introduced in "Hostel."

The "Elite Hunting" corporation, their security noticeably beefed up since last seen, is portrayed in an eerily logical fashion that dodges the far-fetched. So, too, does the events involving Todd and Stuart, rich suburban family men bored by their safe-and-narrow existences and hoping that the act of homicidal slaughter will give them the thrill missing from their lives. That these two fellows are so different—Todd's anticipation is akin to a five-year-old's on Christmas Eve, while Stuart is more hesitant and unsure of himself—leaves one actively curious about how things are going to play out when they come face-to-face with both their victims and the sheer enormity of what they have signed on the dotted line to do.

"Hostel: Part II" is equally as ambitious as "Hostel," and frequently outdoes it in terms of the stark terror it ratchets. Still, it's a more flawed motion picture. Emotionally, the movie is colder and more unforgiving. This is fine in pulling a visceral response from viewers, but the end result is one of downbeat admiration rather than adrenaline-fueled excitement. Once the carnage has subsided and the end credits are rolling, it is easier to say that the film was extremely well-made than to admit you "liked" it. Additionally, the tone is more gravely serious, free of the frat-boy hijinks of the precursor's opening thirty-five minutes. The problem is that it was in that time frame that the viewer got to really know, relate to and care about the three guys. Here, lead actresses Lauren German (2003's "The Texas Chainsaw Massacre"), Heather Matarazzo (2004's "Saved") and Bijou Phillips (2005's "Venom") have less-rounded and complicated characters to work with, their roles barely rising above two-dimensional types. The strong established bond between the young men in "Hostel" was a key component in making them authentic human beings. By comparison, the friendships between these three girls is more sketchy and less palpable; they seem more like acquaintances than buddies.

With that said, it is far more difficult to witness a female meeting a nasty end onscreen than it is a male, and this is where "Hostel: Part II" redeems itself for the less inspired writing of the characters. German, Phillips and Matarazzo are naturally charismatic and identifiable actresses; in other words, they have that crucial likability factor. In the set-pieces where they are placed in harm's way, the film becomes uncomfortable in the extreme. This is no more in evidence than in a sequence of uncommon power involving Lorna, played to the hilt by Heather Matarazzo. I pride myself on having a strong stomach and rarely do horror movies phase me, but this scene is so cruel, so gruesome, so bloody, so sick, so twisted, so unfair and so heartbreaking that it left me feeling physically ill to the point where the end result of vomit was not an impossibility. Eli Roth's unflinching work in this five-minute segment is either that of a genius or that of someone who, undeniable talent aside, crosses a line never before crossed in an R-rated film. In regards to the vulnerable and quirkily lovable Heather Matarazzo, her naked, soul-baring performance is as courageous as any in memory given by a legitimate, mainstream actor. Lofty claims, I know, but also warranted.

The MPAA must have fallen asleep when they screened "Hostel: Part II," which is twice as violent and gory as the already-extreme "Hostel," and more power to them. However Eli Roth got away with some of this material—for those familiar with 1978's hard-core "I Spit on Your Grave," pick out what is widely regarded as the most memorable moment of the climax and imagine it even more explicit—he should be applauded for making the film he set out to make and not holding back from the bad taste that such a storyline honestly consists of. Sitting through it might cause a viewer to feel icky, but at least the movie delivers what he or she has paid to see. The bonus, then, is that a veritable craftsman like Roth is behind the camera; he doesn't make exploitation movies for exploitation's sake, but is an intelligent artist who brings a great deal of sociological layers to his projects.

"Hostel: Part II" has a dreamlike, operatic quality to its look and feel that is nothing like the half-vibrant/half-ashen landscapes of "Hostel." Aided by Milan Chadima's brilliantly sumptuous, almost surreal photography, Roth has made a Grimm's fairy tale for a modern adult audience, and there is no doubt that this was precisely his intention. From the fantastical costumes at the harvest festival, to the stately mansion where the "wolf" takes the prey to pretty her up and give her a false sense of hope before she's "eaten," to the chilling, off-kilter production design of the torture chambers, to the image of a secret room lined with meticulously-mounted severed heads, to the scenes at the hot springs that are as foreboding as they are beautiful, the correlation is unmistakable.

A quick bid for cash without an inkling of thought put into the story, "Hostel: Part II" is not, and the imagination Eli Roth exhibits in lieu of merely repeating himself is a treat. Particularly intriguing this time is its fresh spin on the fight-or-flight method and the compelling comments Roth makes about gender relations—contrast the actions of the boys in the original, both before and after their capture, with the girls in this one—and the dangerously inestimable nature of a person's mental stability, seen most prevalently in the characters of Todd, Stuart and Beth. When all is said and done, "Hostel: Part II" is a very good film, relentless and difficult to shake. While it might be the best horror effort thus far this year, it is also thoroughly unpleasant and will be borderline-inaccessible for all but serious genre buffs. You know who you are, and fortunately I'm one of them.