Deep in Montana's Lolo National Forest, toxic waste is leaking from aged oil drums and mixing with a new batch of biological sludge that has been dumped into a remote lake. It sickens, it mutates, and like cancer, it spreads and devours.
A group of hikers stumble upon bank robbers who've been hiding out in the forest. Held at gunpoint, they soon discover they are being hunted by a vicious predator, and it will take their combined efforts to make it out of the forest alive.