The Descent is British director Neil Marshall's second offering after his cult hit Dog Soldiers, and again sees his foray into the horror genre. While Dog Soldiers was a cheap but cheerful and thoroughly enjoyable werewolf gorefest, The Descent takes a turn for the serious, offering a startling and intense movie that combines visceral shocks with punishing suspense. Although he relies on a simple concept, Marshall achieves the rare feat of tapping into something truly primal with a brutal and at times nihilistic tale, not only of survival, but also of evolution and rebirth. The result is one of the best horror films of the last few years, and one, which deserves to lift the director into the highest ranks of the genre.

The plot is simple but extremely effective. Sarah, Juno and Beth are three old friends who used to engage in all kinds of extreme sports, until Sarah’s husband and daughter died in a car accident that Sarah herself survived. A year later, Juno brings her two friends to the Appalachian Mountains to join a merry little band of thrill-seeking women to do a bit of caving. However, once inside the cave all does not quite go according to plan, as an unexpected rockslide blocks the party’s exit route. At first, the group has to contend with navigating an extremely arduous route out of the cave. But matters get far worse when the six discover they are not alone: the cave is also home sweet home to a band of carnivorous beings that’ve skipped more than a few generations in the evolutionary chain. They’re not too picky about what to chow down on for dinner, and are pretty nifty climbers.

Marshall, who also scripted the movie, populates this familiar scenario with ambiguous, well-written characters, setting up a series of complex, strained relationships from which he wrings every possible drop of tension once things start to go wrong. The result is a sense of depth and gritty realism, and the viewer genuinely feels for the believable characters, making their ordeal all the more terrifying. This is heightened by the fact that quite early on, and in shocking fashion, Marshall makes it clear that he is all too willing to kill off any member of, or perhaps the entire, cast.

It's also very refreshing to see a genre film with a set of strong, female protagonists. The Descent is devoid of the usual clichéd inclusion of cheap romance, or the reliance on male assistance. Although the characters' sex is never made an issue, Marshall does explore some interesting themes, and the catacombs of the horror setting make for an intriguingly womb-like atmosphere. The whole cast is doing very well, particularly Shauna Macdonald as the protagonist Sarah, who convincingly charts her character’s development from fragile, grieving innocent to monster-stabbing, blood-soaked and slightly barmy avenger. But the movie’s standout performance comes from Natalie Mendoza. Although ostensibly the movie’s bad ‘guy’, Mendoza never allows the secret-hiding Juno to become unsympathetic -- rather one who doesn’t know how to properly deal with the events she in part has caused herself.

The Descent is also somewhat reminiscent of the early works of John Carpenter, in particular Halloween (an impression which is accentuated by the score, which seems inspired by, if not slightly derivative of Ennio Morricone's score for The Thing. Other pleasing homages include the descent into madness of Apocalypse Now, and the finale of Carrie). As with Halloween, The Descent is an uncluttered experience of pure horror, freed from the teen-friendly conventions and unnecessary distractions of most modern horror movies. It's also tight and grueling, with dark suggestions lurking beneath its deceptively basic concept, which call for some further analysis.

As befits the setting, The Descent is really all about what’s going on inside, both below us and within the head of the protagonist. Lead character Sarah (Shauna Macdonald) is mentally unstable, still mourning the loss of her husband and daughter. Flashbacks occur throughout the movie, where Sarah’s daughter blows out the candles on her birthday cake -- not a particularly comforting image for a character marooned underground. What puts The Descent above the level of the average monster flick though is its brooding contemplation between the subterranean setting and the characters. Marshall has contrived a superb setting for these sanguine antics and he derives immense dividends by exploiting it fully. They are literally all in a tight spot and Sarah in particular is buried deep within her head and the earth.

One of the delights of Dog Soldiers is the banter between the soldiers, and Marshall continues this here fleshing out his expendables in a lively fashion. These aren’t airbrushed summer break teenagers off to the charnel house (as one character notes: I’m an English teacher, not Tomb Raider). Unlike the men though, these women turn on each other in the face of adversity, fractured by a rift between the leads. Misleadingly described as the ‘sister film’ to Dog Soldiers, this difference between the genders' approach to danger makes The Descent overall a much scarier film and mildly disturbing when you consider that in Dog Soldiers the men stick together against the werewolves, women are referred to as ‘spider bitches’ and the men are betrayed by the female biologist. Marshall does give his characters in The Descent plausible reasons to act as they do and the moment where Juno (Natalie Mendoza), the expedition’s leader, lashes out lethally when the monsters first attack confirms that this is a very different, more sober sort of horror film.

Marshall's direction has improved considerably since his debut, and here he displays a far more measured approach, taking his time and allowing the suspense to build naturally rather than cashing in on any premature exposures of the film's dark heart. He makes impeccable use of the cave settings, generating an at times unbearable sense of claustrophobia, which makes the viewer feel every inch of the characters' growing desperation. His use of color is exemplary, and rather than relying on simple torchlight, he throws in a rich palette of greens, reds and blues, adding an almost otherworldly look to the subterranean landscape. Touches like these, as well as Marshall's clever use of shadows, gives the film a strong visual impact, and makes it deserving to be seen on the big screen.

The film is tautly paced, and Marshall times the shocks and action scenes perfectly, never overplaying his hand during the first half, gradually allowing the viewer to feel trapped along with the characters before unleashing chaos and bloody panic as the creatures attack. By using shaky, handheld camera work, he manages to capture the sudden fury of these assaults, and their unpredictable timing leaves the viewer on edge throughout. As well as relentlessly terrifying, The Descent is unabashedly bloody, and not for the weak of stomach. Marshall never shies away from the gory details, whether showing broken bones or half eaten intestines, and in the latter scenes he really allows the viscera to fly.

However, none of the many head-smashings, eye-gougings or throat-rippings feel gratuitous, mainly due to Marshall's honest, down to earth take on the material. In fact, the film as a whole is not a monster movie in a traditional sense, and Marshall never allows the viewer to forget that it is, in its purest meaning, a story about survival. It is this human element, which makes The Descent not only an exhilarating, heart pounding film of the highest order, but the best that the genre has produced in recent memory.

Underground, no one can see you scream.