In the gripping opening scene, a tribesman traverses the dense rain forest alongside a young child from his tribe. Suddenly, they are startled by the thunderous roar of a bulldozer clearing the land.
Fast forward to the bustling atmosphere at Columbia University in New York City, where we meet Justine (Lorenza Izzo), a bright college student who is attending a harrowing lecture on the oppressive traditions faced by women in various African tribes. Disturbed by the content, she later shares her thoughts with her roommate Kaycee (Sky Ferreira), as they observe a group of janitors engaging in a hunger strike to acquire health insurance—an idea they dismiss as foolish.
One day, Justine receives an invitation from another student, Jonah (Aaron Burns), to visit an activist collective spearheaded by Alejandro (Ariel Levy). The group's mission is focused on the preservation of a tribe nestled deep within the Peruvian jungle. When Justine makes a careless remark about the activists starving themselves in their perilous jungle endeavor, Alejandro reacts defensively and asks her to leave the meeting.
A few days pass, during which Justine seeks out Alejandro to apologize for her insensitivity and expresses her desire to contribute to their cause. Eventually, she and a full entourage of dedicated activists—including Jonah, Alejandro's girlfriend Kara (Ignacia Allamand), Amy (Kirby Bliss Blanton), Samantha (Magda Apanowicz), Lars (Daryl Sabara), and Daniel (Nicolas Martinez)—embark on a flight to Peru, funded in part by Justine’s father. Before takeoff, however, a sense of unease washes over Amy due to the cramped nature of the small aircraft.
Upon arriving in Peru, the group embarks on a boat journey through the lush jungle towards their destination. They make a brief stop for a bathroom break, during which Lars experiences a fright when a tarantula almost bites him.
The group eventually reaches an area where bulldozers are plundering the land. In a valiant act of defiance, they attempt to sabotage the operation with explosives. However, chaos ensues when Justine finds herself at the mercy of a gunman, thrusting the group into a dangerous confrontation that Alejandro films to document the unfolding events. As reality kicks in, Justine is left traumatized and frustrated by the indifference of her companions when her life hangs in the balance.
Soon after, the activists are rounded up and sent back on a plane, taking stock of their supposed victory. But their celebration is cut short when disaster strikes—the plane’s engine fails, culminating in a disastrous crash that claims the lives of both pilots and sends several others hurtling into the darkness.
In the aftermath, the surviving group encounters hostile villagers. Frantic cries for assistance are met with violence, as Kara is struck by an arrow, leading to their hurried retreat. But as they flee, they are subdued with tranquilizers and taken captive by the Cannibal Headhunters of the tribe.
They find themselves imprisoned in wooden cages, helplessly witnessing horrendous acts as Jonah (Aaron Burns) is subjected to grisly torture, culminating in a grotesque feast with his own remains, sent shudders down the spines of the onlookers.
As the horror intensifies, Amy’s deteriorating mental state leads her to an irreversible decision, pushing Justine and Daniel to devise an escape plan. However, hope dims as they face dire circumstances, with each failed attempt leading to tragedy as their friends succumb to horrific fates amidst the revelries of their captors.
Eventually, guided by a native child who rises to assist her, Justine finds a brief glimmer of freedom while leaving behind the others in their dire straits. She stumbles upon a small militia and pretends to film their deplorable actions, leveraging the situation to secure her own escape while her companions face the villagers' wrath.
Returning home, Justine stands as the sole survivor, recounting her tale while burying the grisly truth of what occurred. Struggling with her experiences, she is haunted by dreams of Alejandro and the activists' fate. When she glimpses a group advocating for Alejandro’s return, she is left forced to confront the repercussions of her journey into the heart of darkness.
As the credits roll, a chilling phone call hints at lingering mysteries, with Justine learning from Alejandro's sister that he may still be alive in the jungle, teasing an unsettling end to her nightmare.
