And the moral of the story is: Lost and Abandoned Mayan Temples were usually abandoned and lost for good reasons. Jeff (Tucker), Amy (Malone) and their friends are on holiday in Mexico, when they take a trip to the previously-mentioned L&AMT. However, as soon as they set foot on it, the locals materialize out of the trees and won't let them off, instead chasing the gringos to the top of the pyramid - where a hole descends into the darkness within. Initially, the tourists are prepared to wait it out, but a shortage of resources and the discovery that their lofty perch has perils of its own, force them into making some nasty decisions. Very nasty decisions - not entirely unconnected to Jeff's background as a medical student. Without wishing to give too much more away, they should probably have called this one Jeepers! Creepers!.
The visitors certainly find out why the temple has been abandoned, though the locals' somewhat apathetic attempts at concealing it are surprising. If it had been in my neighbourhood, I would have called in an airstrike or two, rather than just throwing a few branches across the path and hoping for the best. While I'm on the topic of logic, if you want to keep people off your L&AMT, a simple notice explaining why would likely have helped - even if, in this case, it probably began, "You're not going to believe this, but..." It'd reduce your legal liability, at the very least. It needn't even be in English; a simple pictograph, perhaps resembling the one on the lower right, would put the point across very well, and save you from having to round up the entire village to stand guard for days, every time some stupid foreigner stumbles in. There is also the inevitable "no signal" moment, which every wilderness horror film has to get past.
That said, this contains some of the most eye-poppingly nasty gore I've seen in quite some time; it's refreshing to see a horror movie that isn't a remake and feels no need to pander to 14-year olds, with a tone of unrelenting grimness once it gets going. The performances are workmanlike: if no-one has to do much more than look alternately worried and terrified, they deliver both those expressions credibly enough. The actors are likely helped by the threat in question, which is one of the creepiest - at least, to me - to come down the horror pipeline in some time, and the characters cracking under pressure is entirely understandable. Despite an infuriatingly indefinite ending [if you can't think of half-a-dozen ways to improve it, you aren't trying], as mainstream horror goes, this is probably among the best of the year.