As the curtain opens on The Descent, we see a group of long-time friends—Sarah, Juno, Beth, Sam and Rebecca—wrapping up another one of their annual wilderness adventures. This time, it’s a whitewater rafting expedition, and as they all get ready to go back home, we see that there’s something wrong between Sarah and her husband. He seems like he has something important to tell her, but he never gets that chance because moments later, he accidentally drifts their car across the center lane and into an oncoming logging truck. The impact instantly kills Sarah’s husband and their young daughter Jessica, but miraculously spares Sarah. That Juno never visits Sarah in the hospital after the crash, or comes to console Sarah later suggests that Juno wasn’t just being insensitive. She was grieving her own loss. And for Sarah, that raises questions about her husband that she would probably like left unanswered.
Juno’s plan to heal the rift between them is to have one last great adventure together, so she calls the friends back a year later for another outing as if nothing ever happened. This time, they bring along a newcomer, Holly, and they head out to the North Carolina Appalachians for a caving expedition. At first, it looks like Juno has really scored; the trip is in an unbelievable cavern system the rest of the group did not realize was open to the public, one of those best kept secrets that thrill junkies live for. But it all goes sideways when a cave-in traps the ladies beneath the earth, and Juno reveals that they are in an unexplored system; she thought she would make their trip extra-special by leading them through a place nobody has ever seen before.
Moments later, the ladies are attacked by a tribe of Gollum-like creatures who prove that technically, Juno was right. Nobody has seen these caves before, but only because the monsters who live here have evolved for life in total darkness and don’t have eyesight. What follows is an intense stretch of survival horror as the group tries to find a way to the surface, all while being hunted down and eaten alive. Throats are ripped out, heads are bashed in, pick axes are wielded like battle axes, collateral damage is inflicted, people save each other, people lose each other, people betray each other, and those creepers keep popping up and scaring the hell out of you at every corner.
Meanwhile, Sarah—the most emotionally fragile member of the group—finds a weird kind of resolve to survive by channeling the memory of her lost daughter, and along the way, she transforms into somebody that she very much is not back on the surface. The movie’s big showdown isn’t between Sarah and the creepers, its when she finally reunited with Juno. Juno, who got them all trapped down here. Juno, who might have accidentally killed one of their own during the fight with the creepers. Juno, who might have slept with Sarah’s husband and indirectly caused the accident that killed Sarah’s daughter. With the entire tribe of underfolk closing in, we wonder, will Sarah and Juno work together to survive, or is Sarah going to settle their personal business right here and now?
This is the movie’s moment of truth, because we see a madness in Sarah’s eyes that has been simmering ever since she lost her family, and has been brought forth by her extreme environment and horrific circumstances. I have gone spelunking before. I can tell you, being deep in a challenging cavern system is an assault on your senses and on both your mental and physical stamina. You put a traumatized accident survivor down there and have her fight off devolved cannibal people for a few hours, and anything’s likely to happen. You know that however this situation between Sarah and Juno resolves itself, it’s not a matter of right and wrong, it’s a matter of primal instinct. And instinct does what has to be done.
This bloody descent into the depths of the earth, like in any good horror story, strips its characters of the conventions of civility and morality that we all live by. But as we see these things fall away, we are reminded in the starkest terms possible that these things can fall away. We are moral and civil creatures because we choose to be…until we are put under the right set of circumstances that make that choice no choice at all. We don’t have to evolve underground to become monsters. We just have to let the monsters within us to crawl to the surface. It’s easier than we think.