The closest I’ve ever come to cave exploring was on Tom Sawyer’s Island at Disneyland. Granted, some of the tourists coming from the opposite direction were pretty scary, but nothing compared to the horrors that await six women spelunkers in The Descent.

Following close on the heels of The Cave and the direct-to-video The Cavern, The Descent is the best of the lot, a claustrophobic thriller which mixes bits and pieces of other horror films into a heart-stopping nightmare. Writer-director Neil Marshall (Dog Soldiers) takes us down a familiar rabbit hole, but once the bunnies start biting, all bets are off.

Marshall keeps The Descent tight and compact. He doesn’t waste a lot of time on backstory. The Descent opens up with a white-water rafting trip which introduces us to key characters. The rafting trip is visual shorthand to show us how the women enjoy a good challenge and are able to come together in a crisis.

A year after the rafting trip and a tragic accident that left team member Sarah (Shauna Macdonald) emotionally scarred, the women gather for a cave

expedition in the Appalachian Mountains. Team leader Juno (Natalie Mendoza), a professional climber, has confidence to spare. Rebecca (Saskia Mulder) is joined by half sister Sam (MyAnna Buring), a medical student looking for one last big adventure before graduation. They are joined by Sarah’s best friend, teacher Beth (Alex Reid) and High Times calendar girl Holly (Nora-Jane Noone).

After a night of partying and reflection, the women grab their equipment and make their des-cent. Spelunking, by nature, is filled with inherent dangers: cave-ins, floods, unexpected falls, depletion of oxygen. With all those variables, it’s up to the spelunker to know her stuff, have her act together and keep her head when something happens. It does, and almost immediately.

The Descent is a horror film, so it doesn’t take long before the team breaks all three rules. When Juno learns of a new cave chamber, she sees an opportunity to lead the team into the history books: first in, first out, name the cave. Unfortunately, Juno doesn’t file her plans, so the women are on their own. After a jaw-dropping descent into the main cavern, the team begins crawling through one tight tunnel after another.

It’s during these precious few moments of sanity that we discover each woman’s flaw, her fears, and how those fears will play out in the most devastating ways. After a cave-in, the women are left to their own devices. Too bad there’s something lurking in the dark, something ugly and slimy and very, very hungry.

What distinguishes The Descent from other cave thrillers is the way director Marshall never lets up, constantly pounding at us until our heartbeats becomes so loud we can no longer hear the characters scream. Scream they do, as each woman encounters the crawlers, hillbilly mutants who have evolved into bat-like creatures. They can’t see, but they have terrific hearing, and when the screaming starts, the buffet is open for business.

Vicious is the only way to describe what happens next, as Juno, Sarah and the other characters draw inner strength to survive, putting a number of crawlers in their places before losing their own lives. Marshall effectively uses light and erratic camera angles to frequently catch us off guard, keeping us as disoriented as the characters.

None of the women gives up without a fight, and when they strap on their Rambo gear and go mutant-hunting, you know they mean business. That doesn’t stop the slaughter, but it does make the eventual showdown much more harrowing.

Marshall has my respect for making something out of nothing. Dark house movies are a dime a dozen, yet Marshall and his actors invest much more into The Descent. The film is a gripper.