Eli Roth’s tribute to the grotty cannibal movies of the late 1970s is horrifying to behold, perhaps even more so because it’s far easier to empathize with his characters than in his past works.

They are a bright and engaging lot, a passionate group of environmentalists who want to save the rain forest. College freshman Justine (Lorenza Izzo) is initially attracted by the smoky good looks of Alejandro (Ariel Levy), a charismatic protester, but the group’s intentions strike a chord. Like many young people, she’s been looking for a movement that she can get behind. And besides, Alejandro is so cute!

Soon enough, Justine finds herself the least-experienced protester in the group, yet nonetheless flying down to South America. She receives brisk instructions as the group proceeds to their destination, attempting to halt construction crews from clearing the forest for new development, but is a bit dismayed to find herself tied up to a tree. Alejandro turns even more fiery toward the construction workers, but his callous disregard of Justine’s feelings, as well as her realization that he’s already involved with one of the other protesters, cools her personal leanings toward him.

Still, the protest succeeded, and everyone is happy, until the plane develops mechanical problems and crash lands in the jungle. Not everyone survives, but the survivors will envy the dead very soon, because they have landed in the territory of a native tribe that always appreciates new sources of protein, such as defenseless humans.

From there, it’s clear where the movie will go: heartless cannibals versus victims who will soon be without hearts. How could that turn out to be anything but gruesome, especially in the hands of Eli Roth?

Roth, as you might expect, takes things to extremes in his depiction of the cruel, explicit violence visited upon the protesters, who are absolutely helpless, caged in public view, where they soon turn against one another. What makes the violence more disturbing is that the protesters are young, earnest, and idealistic. Occasionally they come across as shrill or overbearing, but, frankly, that describes nearly all the protesters I’ve known in real life: the issues that they are up in arms about are more important to them than how they present themselves.

Now, that changes later in the story, but the more sympathetic, recognizable nature of nearly everyone in the group creates a rooting interest for the audience, which is especially important since we know their chances for survival are extremely slim. Make no mistake, however, the violence, when it comes, is extremely bloody and gory, which may be stomach-turning for more sensitive viewers (who probably shouldn’t be watching this movie, anyway).

If you are an adventurous horror movie fan, The Green Inferno is likely to keep you up at night, watching characters get torn apart, and hoping against hope that some of them will survive.