Apex

While tandem climbing the Troll Wall in Norway, adrenaline junkie couple Sasha and her Australian boyfriend Tommy are caught in a storm. He tells her that his lucky compass is warning him that their luck may have run out, so they decide to rappel back down. A rock from an avalanche hits him in the head and knocks him off the wall; the weight of his unconscious body pulls at her, and she, being unsure if he is still alive, is forced to release his rope. He plummets to his death.

Five months later, a grieving Sasha drives alone towards the fictional Wandarra National Park in Australia; a ranger warns her of a string of disappearances in that region. She stops at a service station where she has a tense encounter with two hunters, who leave after a stranger intervenes. Sasha buys a bag of jerky given to the store by the stranger. The stranger, Ben, then gives Sasha directions to Grand Isle Narrows, starting at Blackstone Bay.

The hunters confront Sasha at the bay, but she dismisses them and they leave without causing trouble. The next day, she kayaks through the rapids and camps overnight, but she wakes to find her bag missing. She stumbles across Ben's camp, where he offers her breakfast and additional supplies. He hints that he knows about her climbing past and tells her he was watching her at the bay. He also admits to stealing her bag. A frightened Sasha attempts to leave. Ben then brings out a crossbow and a boombox, telling her she has until the end of one song before he starts hunting her.

Running from Ben's camp, Sasha escapes on her kayak but loses it on the rapids. She runs up a hill and hears voices of a nearby family, only to find it is a video recording planted to lure her. Ben shoots at her, forcing her back into the river. She reaches a ravine and attempts to steal an empty canoe from Ben but triggers a bear trap. Ben takes Sasha to a nearby cave where he chains her up and the carcasses of many missing people are hidden, including the four members of the family in the video.

Ben reveals he is a practitioner of cannibalistic tribal rituals, and is turning people into jerky. Ben explains that he has consumed others, including his mother, and that he intends to do the same to Sasha. Sasha bites one of Ben's ears off and escapes from her shackles, fleeing down river. Ben follows and manages to attach himself to a cable she had been suspended by, but when they go over a waterfall he is knocked unconscious. While Sasha attempts to break her bonds, he regains consciousness and overpowers her. She knocks him off her and, using a rock, gives his leg a compound fracture.

At night, Sasha tells Ben she feels guilt for letting Tommy fall to his death. In the morning, the pair reaches a wary compromise: they will conduct a tandem climb up a sheer cliff and out of the canyon. Otherwise, Sasha would have to wait days for Ben to die of an infection while remaining shackled to him. Ben promises to unshackle her when they reach the top of a nearby cliff. Sasha fashions a Prusik knot to help Ben pull himself up. While climbing, Sasha stops at a ledge and discreetly loosens her harness, but when Ben notices and tries to pull her off the cliff, her harness slips off. She removes the knot holding him and Ben falls to his death. Sasha continues the climb, now without gear, and reaches the top of the wall.

Sasha walks through the forest in the dark and is rescued by a passer-by who drives her back to Blackstone Bay. She returns to the ranger station and explains to the ranger where the missing family is. Their bodies, along with at least 16 others, are recovered from Ben's hideout. Amidst a news report of this, Sasha goes to a beach and throws Tommy's compass into the ocean.