The hiker, named Sarah, is on a solo backpacking trip through the wilderness. After getting lost, she comes across an old cabin and decides to seek shelter for the night. The cabin belongs to a man named Harold, who at first seems friendly but quickly reveals himself to be unpredictable and possibly mentally unstable.
As the night wears on, Sarah realizes that Harold is not what he seems. He rants about government conspiracies and talks about a mysterious "experiment" that he claims to be a part of. Sarah becomes increasingly uncomfortable and begins to fear for her safety.
To make matters worse, Harold seems to be fixated on Sarah and won't let her leave the cabin. She starts to suspect that he may have sinister intentions, and resolves to find a way to escape.
As the two of them engage in a tense standoff, it becomes clear that they are both hiding secrets. Sarah must use all of her strength and resourcefulness to survive the night and outsmart Harold, who may be more dangerous than she ever could have imagined.