This movie really never lets up, once they really get in peril. A group of women meet to go cave exploring (spelunking), into a cave that is well known, and not too dangerous. Except that Juno decides that is not the cave for them, and takes them into a totally unknown cave. A cave that was not on file with the authorities in the event they did not report in after the set time. There is a cave in, trapping them and they need to find a way out. One gets a sense of the physical strength needed in caving, and also that some of them are really not all that up to it. And there are lots of tension among the group members. The compound fracture one of them suffers is rather hard for the squeamish to see, and it is graphic. And things really go downhill for all of them, as creatures are present in the cave, and those creatures are hungry. There is a lot of gore, and horrible deaths. Not deaths done horribly, but deaths that are horrible. One by one the group gets smaller. There is a lot of tension, and a lot of suspense. It captures what it is like to be in a cave system. It is a good thrill ride, and better than I expected.